Drop SKIP_OBS

Commit 85802ab7 "HACK: Skip OBS scanning by default" worked around a
performance issue with the initial deploymento of OBS 2.10.

With ce731f22 "Do not skip OBS scan" it got re-enabled again, albeit
needing more time than before.

Time to drop the hack.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>