Use env variables as rules

.gitlab-ci.yml

@@ -145,6 +145,9 @@ build_poiseuille_test_container:
 
   stage: container_upload
 
+  rules:
+    - if: $REMOTE_USER && $REMOTE_HOST && $PRIVATE_KEY
+
   tags:
     - linux
     - privileged
@@ -212,6 +215,9 @@ gcc_9_python_hpc_test:
 
   needs: ["build_poiseuille_test_container"]
 
+  rules:
+    - if: $REMOTE_USER && $REMOTE_HOST && $PRIVATE_KEY
+
   before_script:
     - pip install hpc-rocket