<oo-admin-check-sources.py> Bug 1025147, give repo disable instructions according to repo subscription type
https://bugzilla.redhat.com/show_bug.cgi?id=1025147

Group conflicting repos by subscription type and print appropriate
instructions for each group. UX could probably stand improvement here

Also adds blank line between role validation and version/subscription
detection output and repo advice output
Merge pull request #131 from dobbymoodge/check-sources-bugs

<oo-admin-check-sources.py> Bug 1025147, give repo disable instructions according to repo subscription type