upstream-update - send candlepin capabilities to upstream distributor

During 'Refresh Manifest' steps, the first one now is to send the installed candlepin's capabilities to the upstream distributor (either the customer portal or another katello). This informs the upstream what subscription capabilities the downstream candlepin can handle.

upstream-update - changes based upon feedback
upstream-update - replaced instance_eval with send
Merge pull request #2611 from thomasmckay/upstream-update

upstream-update - send candlepin capabilities to upstream distributor