Make gerrit_refspec parameters optional

Change-Id: If3dbd009d59f75d9b9f9556c5ece32a40890a383
Issue-ID: INT-584
Signed-off-by: Gary Wu <gary.i.wu@huawei.com>
diff --git a/deployment/heat/onap-oom/parts/onap-oom-1.yaml b/deployment/heat/onap-oom/parts/onap-oom-1.yaml
index 5f117ac..1a9e33d 100644
--- a/deployment/heat/onap-oom/parts/onap-oom-1.yaml
+++ b/deployment/heat/onap-oom/parts/onap-oom-1.yaml
@@ -46,7 +46,7 @@
 
   integration_gerrit_refspec:
     type: string
-    default: "refs/heads/master"
+    default: ""
 
   oom_gerrit_branch:
     type: string
@@ -54,7 +54,7 @@
 
   oom_gerrit_refspec:
     type: string
-    default: "refs/heads/master"
+    default: ""
 
   docker_manifest:
     type: string