Install tempest dependencies with constraints

to prevent dependencies drift if they are not specified as dependencies
of any tempest plugin.

Change-Id: I0553cf216090bf1d582b5863137cec0b3af7d35b
Related-Issue: PROD-35031
diff --git a/extra/pre-build.sh b/extra/pre-build.sh
index 29aa4e1..581d76a 100755
--- a/extra/pre-build.sh
+++ b/extra/pre-build.sh
@@ -116,6 +116,7 @@
   done
   echo "=== Installing tempest itself"
   pushd /var/lib/tempest/
+    pip install --constraint /var/lib/openstack_requirements/upper-constraints.txt -r requirements.txt
     pip install .
   popd
   pip install junitxml