Address Deprecation Warnings (Erlang 20.3)

[tisba]

While compiling Tsung against Erlang 20.3 (erts-9.3) I noticed the following deprecation warnings, that we might want to address soonish.

As far as I can tell we have these kinds of warnings:

• the 'random' module is deprecated; use the 'rand' module instead
• gen_fsm:start_link/4 is deprecated and will be removed in a future release; use gen_statem:start_link/4
• gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2 and
• gen_fsm:start_link/3 is deprecated and will be removed in a future release; use gen_statem:start_link/3

All deprecation warnings:

src/tsung/ts_utils.erl:165: Warning: random:seed/3: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_utils.erl:174: Warning: random:seed/3: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_utils.erl:176: Warning: random:seed/3: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_utils.erl:765: Warning: random:uniform/1: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_utils.erl:770: Warning: random:uniform/1: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_utils.erl:782: Warning: random:uniform/1: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_launcher.erl:62: Warning: gen_fsm:start_link/4 is deprecated and will be removed in a future release; use gen_statem:start_link/4
src/tsung/ts_launcher.erl:70: Warning: gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2
src/tsung/ts_launcher.erl:75: Warning: gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2
src/tsung/ts_launcher.erl:80: Warning: gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2
src/tsung/ts_launcher.erl:227: Warning: random:uniform/1: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_bosh.erl:279: Warning: random:uniform/1: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_launcher_static.erl:56: Warning: gen_fsm:start_link/4 is deprecated and will be removed in a future release; use gen_statem:start_link/4
src/tsung/ts_launcher_static.erl:64: Warning: gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2
src/tsung/ts_launcher_static.erl:69: Warning: gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2
src/tsung/ts_launcher_static.erl:77: Warning: gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2
src/tsung/ts_session_cache.erl:200: Warning: random:uniform/1: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_stats.erl:58: Warning: random:uniform/1: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_stats.erl:62: Warning: random:uniform/0: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_stats.erl:70: Warning: random:uniform/0: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_stats.erl:89: Warning: random:uniform/0: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_stats.erl:117: Warning: random:uniform/0: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_stats.erl:118: Warning: random:uniform/0: the 'random' module is deprecated; use the 'rand' module instead
src/tsung/ts_client.erl:58: Warning: gen_fsm:start_link/3 is deprecated and will be removed in a future release; use gen_statem:start_link/3
src/tsung/ts_client.erl:66: Warning: gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2
src/tsung/ts_cport.erl:80: Warning: random:uniform/1: the 'random' module is deprecated; use the 'rand' module instead
src/tsung_controller/ts_file_server.erl:154: Warning: random:uniform/1: the 'random' module is deprecated; use the 'rand' module instead
src/tsung_controller/ts_user_server.erl:280: Warning: random:uniform/1: the 'random' module is deprecated; use the 'rand' module instead
src/tsung_controller/ts_config_server.erl:568: Warning: random:uniform/0: the 'random' module is deprecated; use the 'rand' module instead
src/tsung_controller/ts_config_server.erl:605: Warning: random:uniform/0: the 'random' module is deprecated; use the 'rand' module instead
src/tsung_controller/ts_config_server.erl:607: Warning: random:uniform/0: the 'random' module is deprecated; use the 'rand' module instead
src/tsung_controller/ts_timer.erl:55: Warning: gen_fsm:start_link/4 is deprecated and will be removed in a future release; use gen_statem:start_link/4
src/tsung_controller/ts_timer.erl:59: Warning: gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2
src/tsung_controller/ts_timer.erl:63: Warning: gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2
src/tsung_controller/ts_timer.erl:66: Warning: gen_fsm:send_event/2 is deprecated and will be removed in a future release; use gen_statem:cast/2