Update package-building unit tests

Update package-building unit tests

Various updates to unit tests of Python package-building scripts.

Adds Fluorine, Fluorine SR1 and Oxygen SR3 coverage.

Doesn't update old snapshot and multipatch URLs as they don't actually
need to resolve, the logic uses the URL itself. This is unlike the tests
in RelEng/Builder that require frequent updates since they actually
interact with the remote artifacts.

Change-Id: Idd471f3663fa7fb1cba9558cbd8fef0f0d858755
JIRA: INTPAK-223
Signed-off-by: Daniel Farrell <dfarrell@redhat.com>