Update .gitlab-ci.yml

.gitlab-ci.yml

@@ -13,7 +13,7 @@ build-mlmc:
     - module add Anaconda3
 
   script:
-    - if [ -n "$VAR" ]; then
+    - if [ -n "$UPSTREAM_COMMIT" ]; then
     -   echo "Using referenced mpp commit"
     - else
     -   echo ${UPSTREAM_COMMIT}