fix #15 EOFError w/ Net::HTTP in 1.8.7

Attempting to fix issue #15

Switched up the syntax of this Net::HTTP request because 1.8.7 doesn't
support passing use_ssl as an argument in this manner, resulting in
EOFError when Net::HTTP makes request to https endpoints.

Should be forward compatabile with 1.9 as well

I'm not to familiar with testing best practices for Mocha, so open to feedback [on this part](https://github.com/clifff/garb/pull/new/issue_15#L1R135) in particular. It does work in 1.8.7 now though!