Use the correct path for upper-constraints
requirements is at /home/jenkins/openstack/requirements let's use it.
virtualenv -p {python} env
- export UPPER_CONSTRAINTS_FILE=$WORKSPACE/requirements/upper-constraints.txt
+ export UPPER_CONSTRAINTS_FILE=$(pwd)/openstack/requirements/upper-constraints.txt
sed -i '/^diskimage-builder/d' $UPPER_CONSTRAINTS_FILE
./env/bin/pip install $(pwd)/openstack/diskimage-builder -c $UPPER_CONSTRAINTS_FILE
