Fix incorrect conditions for skipping builds

Before the runner changes, if OSC_CONFIG was null / empty, we would avoid running any builds. Once the runner was added, though, this became a bit of a mess:

• Non-runner builds now also use OBS_USER, but that wasn't part of the condition.
• The runner uses OBS_SERVER & OBS_PASSWORD instead of OSC_CONFIG, but there were no conditions for this one at all.

This updates these conditions to match the variables that runner/non-runner builds do, in fact, actually require.

https://phabricator.apertis.org/T9003

Signed-off-by: Ryan Gonzalez ryan.gonzalez@collabora.com