Merge branch 'tiagogomes/ci-minor-tweaks' into 'master'

Minor CI tweaks

See merge request BuildStream/buildstream!842
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a523dca..239f30f 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -161,14 +161,14 @@
 .overnight-tests: &overnight-tests-template
   stage: test
   variables:
-    bst_ext_url: git+https://gitlab.com/BuildStream/bst-external.git
-    bst_ext_ref: 1d6ab71151b93c8cbc0a91a36ffe9270f3b835f1 # 0.5.1
-    fd_sdk_ref: 88d7c22c2281b987faa02edd57df80d430eecf1f # 18.08.12
+    BST_EXT_URL: git+https://gitlab.com/BuildStream/bst-external.git
+    BST_EXT_REF: 1d6ab71151b93c8cbc0a91a36ffe9270f3b835f1 # 0.5.1
+    FD_SDK_REF: 88d7c22c2281b987faa02edd57df80d430eecf1f # 18.08.11-35-g88d7c22c
   before_script:
   - (cd dist && ./unpack.sh && cd buildstream && pip3 install .)
-  - pip3 install --user -e ${bst_ext_url}@${bst_ext_ref}#egg=bst_ext
+  - pip3 install --user -e ${BST_EXT_URL}@${BST_EXT_REF}#egg=bst_ext
   - git clone https://gitlab.com/freedesktop-sdk/freedesktop-sdk.git
-  - git -C freedesktop-sdk checkout ${fd_sdk_ref}
+  - git -C freedesktop-sdk checkout ${FD_SDK_REF}
   only:
   - schedules