Supporting yum_clone_distributor in pulp

This assigns 2 distributors to all repos, a yum_distributor
and a yum_clone_distributor.  This way we can call the yum_clone_distributor
in some cases when we know we are cloning a repository.  This really
is only the case in content view promotion.
updating spec for katello-pulp-plugins
fixing test looking for distributors
small formatting fix
cassette update
spec test fix
styling fixes
Merge pull request #2719 from jlsherrill/faster_publish

Using a custom pulp distributor to speed up Content view publish