<oo-admin-check-sources.py> Bug 1022828 - fix subscription/version detection

Added logic to guess_ose_version to fall back on existing repos to
determine subscription type if no blessed repos are available

Improved subscription/version output
Merge pull request #107 from dobbymoodge/check-sources

<oo-admin-check-sources.py> Bug 1022828 - fix subscription/version detection