Update CIAB branch to cord-4.0

Change-Id: Iccc514e65e5676474440b59e9f966f3e127406a5
diff --git a/scripts/cord-bootstrap.sh b/scripts/cord-bootstrap.sh
index 675c7f5..bfe90e7 100755
--- a/scripts/cord-bootstrap.sh
+++ b/scripts/cord-bootstrap.sh
@@ -29,7 +29,7 @@
 MAKECMD="${MAKECMD:-make -j4}"
 
 # CORD versioning
-REPO_BRANCH="${REPO_BRANCH:-master}"
+REPO_BRANCH="${REPO_BRANCH:-cord-4.0}"
 
 # Functions
 function run_stage {