Update pip and add requirements.txt

Related-Prod: PROD-36337
Change-Id: Ic1a4c1127a79d6e257115f062cbdd0eef18cb755
diff --git a/extra/pre-build.sh b/extra/pre-build.sh
index 0e97d6a..7581983 100755
--- a/extra/pre-build.sh
+++ b/extra/pre-build.sh
@@ -36,8 +36,7 @@
   # TODO migrate to downstrem mirror?
   mkdir -p data; pushd data
     if [ ! -d openstack_requirements ] ; then
-      git clone https://github.com/openstack/requirements.git openstack_requirements
-      pushd openstack_requirements; git checkout $UPPER_CONSTRAINTS_TAG; popd
+      mv ../openstack_requirements .
     fi
     sed -i -e "s|tempest=.*|git+file:///var/lib/tempest@${TEMPEST_TAG}#egg=tempest|g" \
     openstack_requirements/upper-constraints.txt;