Bind "H" short option to --hostname

fake-s3 already binds "h" to --help:

$ fakes3 -h 127.0.0.1 -p 8080 -r /tmp/fakes3/
ERROR: "fakes3 help" was called with arguments ["127.0.0.1", "-p", "8080", "-r", "/tmp/fakes3/"]
Usage: "fakes3 help [COMMAND]"