Remove extraneous unwrap()

[royallthefourth]

env_logger::init() panics rather than returning an error, so unwrap() causes a compile error here.

[mwarning]

I had to remove unwrap() in order to compile simple-server.

My dependencies:

simple-server = "0.3.0"
log = "0.4.0"
env_logger = "0.5.13"