Investigate HipChat integration test failures

[christophermaier]

HipChat integration tests appear to be failing in Travis CI. The following is representative of the failing output.

     ** (MatchError) no match of right hand side value: {:error, {%RuntimeError{message: "Error: Timeout waiting for bot to join room: [email protected]"}, [{Cog.Test.Support.HipChatClient, :wait_for_join, 1, [file: 'test/support/hipchat_client.ex', line: 72]}, {Cog.Test.Support.HipChatClient, :"-init/1-fun-0-", 3, [file: 'test/support/hipchat_client.ex', line: 55]}, {Enum, :"-each/2-lists^foreach/1-0-", 2, [file: 'lib/enum.ex', line: 651]}, {Enum, :each, 2, [file: 'lib/enum.ex', line: 651]}, {Cog.Test.Support.HipChatClient, :init, 1, [file: 'test/support/hipchat_client.ex', line: 51]}, {:gen_server, :init_it, 6, [file: 'gen_server.erl', line: 328]}, {:proc_lib, :init_p_do_apply, 3, [file: 'proc_lib.erl', line: 247]}]}}
     stacktrace:
       test/integration/hipchat_test.exs:18: Integration.HipChatTest.__ex_unit_setup_2/1
       test/integration/hipchat_test.exs:1: Integration.HipChatTest.__ex_unit__/2
     The following output was logged:
     2017-08-20T02:52:54.693 module=Romeo.Roster line=16 [info]  Getting roster items
     2017-08-20T02:52:54.806 module=Romeo.Transports.TCP line=30 [info]  Established connection to chat.hipchat.com
     2017-08-20T02:52:54.866 module=Romeo.Transports.TCP line=95 [info]  Negotiating secure connection
     2017-08-20T02:52:54.928 module=Romeo.Transports.TCP line=100 [info]  Connection successfully secured
     2017-08-20T02:52:54.957 module=Romeo.Auth line=47 [info]  Authenticating with PLAIN
     2017-08-20T02:52:55.098 module=Romeo.Auth line=81 [info]  Authenticated successfully
     2017-08-20T02:52:55.161 module=Romeo.Transports.TCP line=133 [info]  Bound to resource: none||proxy|pubproxy-b600.hipchat.com|5252
     2017-08-20T02:52:55.190 module=Romeo.Transports.TCP line=149 [info]  Session established
     2017-08-20T02:52:55.232 module=Romeo.Roster line=16 [info]  Getting roster items