MDLSITE-2664 Send feedback to the tracker on error

There are some small checks built in the bulk checker
detecting basic errors (missing repository, no branches...)
and they, right now, are preventing the Tracker to get
notified about them (information only remains @ jenkins).
With this change, the tracker will be notified, so everybody
knows about those basic mistakes.

NOTE: This commit also includes some small changes to output.
MDLSITE-2665 CS will only check .php files for now