Merge "Fix installing tempest plugins"

Author: Zuul

lib/tempest

@@ -672,7 +672,7 @@ function install_tempest_plugins {
     pushd $TEMPEST_DIR
     if [[ $TEMPEST_PLUGINS != 0 ]] ; then
         # The requirements might be on a different branch, while tempest & tempest plugins needs master requirements.
-        (cd $REQUIREMENTS_DIR && git show master:upper-constraints.txt) > u-c-m.txt
+        (cd $REQUIREMENTS_DIR && git show origin/master:upper-constraints.txt) > u-c-m.txt
         tox -evenv-tempest -- pip install -c u-c-m.txt $TEMPEST_PLUGINS
         echo "Checking installed Tempest plugins:"
         tox -evenv-tempest -- tempest list-plugins