use the right devstack sha
diff --git a/tools/build_uec.sh b/tools/build_uec.sh
index 240ea78..cb1ce2d 100755
--- a/tools/build_uec.sh
+++ b/tools/build_uec.sh
@@ -173,6 +173,9 @@
 apt-get install git -y
 git clone https://github.com/cloudbuilders/devstack.git
 cd devstack
+git remote set-url origin `cd $TOP_DIR; git remote show origin | grep Fetch | awk '{print $3}'`
+git fetch
+git checkout $GIT_COMMIT
 cat > localrc <<EOF
 `cat $TOP_DIR/localrc`
 EOF