Description of problem:
Satellite 6 is on a network, behind a proxy. To be able to sync content from Red Hat or other external repos the Satellite will have too go trough the proxy.

There are also internal repos on the network, the proxy server cannot access these, but the Satellite itself can access them. 

Version-Release number of selected component (if applicable):


How reproducible:
Reproducable

Steps to Reproduce:
1. Install Sat on network behing proxy, enable the --katello-proxy-* options.
2. Set up yum repo on another system on the repo, served via http.
3. Create a product, and a repo.
4. Add the http://<....> URL for the yum repo on the server on the internal network.
5. If the proxy cannot access the internal repo, sync will fail.

Actual results:
Sync fail because proxy cannot access the host serving the internal repo.

Expected results:
A "no_proxy" option should be available to allow configuration of domans, subnets, hosts etc that Satellite should not use the proxy to access.

Additional info: