Make sure that a few temporary artifacts are removed
Since 24b21acd, the l10n pseudo-module is not processed anymore on the stable branch (maybe in the end it didn't really hurt, but less logically correct).
But processing the svn-based l10n pseudo-module meant that, when the script
requested the removal of some generated artifacts (like the all_files_*),
it was in the correct directory (for example /prod/branches/stable/l10n-kf5,
where BASEDIR=/prod and transmod=branches/stable/l10n-kf5).
Now this assumption does not hold anymore: the current directory is
the directory of the clone of the last git modules processed.
So, just move back to $BASEDIR and remove the files from there.
Maybe the removal of messages is not needed anymore but keep it here for now. A better solution would be moving all those temporary artifacts into a temporary directory.