rpmgs: warn instead of fatal when HEAD unchanged, continue to refresh vendored sources

bin/rpmgs

@@ -1144,12 +1144,12 @@ fi
 			echog "Try to fetch ${GETSOURCEGIT} for $spec"
 			#TODO error if incompatible
 			HEAD_BEFORE=$(git rev-parse HEAD)
-			docmd git remote add upstream $GETSOURCEGIT
+			docmd git remote add upstream $GETSOURCEGIT 2>/dev/null || :
 			docmd git fetch --tags upstream
 			update_master_branch_to "$GSSETVERSION"
 			HEAD_AFTER=$(git rev-parse HEAD)
 			if [ "$HEAD_BEFORE" = "$HEAD_AFTER" ] ; then
-				fatal "Sources were not updated: HEAD unchanged after merge. Check upstream URL and tag."
+				warning "HEAD unchanged after merge — upstream has no newer code, continue with vendored sources refresh only."
 			fi
 			FIRSTSOURCEGIT=1