Changed implementation of proxy setup

Changed the setup_http_proxy method to setup_proxy.
The same arguments are used as before. This change includes
workarounds for pulp proxy configuration. However, until BZ1114083
is fixed, easier proxy support will not be possible.
this remains from the setup_http_proxy it replaced. i simply rearranged the order to flow better.

also, i would like to keep the ability for someone to test against a local proxy that may have an entry in their hosts file. if you guys think that isn't necessary, then i am fine with changing.