bsmailusers: ignore commit/mail steps if FILES list is empty

bin/bsmailusers

@@ -234,6 +234,9 @@ do
 			done
 			echo "" >> $MAIL
 		done
+                if [[ -z "$FILES" ]]; then
+                    continue
+                fi
 		echo "Commiting updates to https://gitlab.cern.ch/linuxsupport/websites/linux.cern.ch"
 		$BIN/bscommitupdates -d $DIST -r $REPO
 		printf "$FOOTER" >> $MAIL