use bash a bit better

ci-tools/update-production

@@ -44,7 +44,7 @@ ensure_changes() {
     local TARGET_BRANCH=$1
     shift
 
-    if [ $(git rev-parse origin/"$SOURCE_BRANCH") -eq $(git rev-parse origin/"$TARGET_BRANCH") ]; then
+    if [ "$(git rev-parse origin/"$SOURCE_BRANCH")" = "$(git rev-parse origin/"$TARGET_BRANCH")" ]; then
 	return 1
     fi
 }