Fixes 'warning: loading in progress, circular require considered harmful'

[grzuy]

Minimal steps to reproduce:

$ gem install rails
$ gem install hipchat
$ echo "require 'rails'" >> hipchat_test.rb
$ echo "require 'hipchat'" >> hipchat_test.rb
$ ruby -w hipchat_test.rb
... ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:120: warning: loading in progress, circular require considered harmful ...

[rberrelleza]

Thanks!