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/onap-oom.yaml b/deployment/heat/onap-oom/onap-oom.yaml
index e6845cc..44b23e4 100644
--- a/deployment/heat/onap-oom/onap-oom.yaml
+++ b/deployment/heat/onap-oom/onap-oom.yaml
@@ -49,7 +49,7 @@
 
   integration_gerrit_refspec:
     type: string
-    default: "refs/heads/master"
+    default: ""
 
   oom_gerrit_branch:
     type: string
@@ -57,7 +57,7 @@
 
   oom_gerrit_refspec:
     type: string
-    default: "refs/heads/master"
+    default: ""
 
   docker_manifest:
     type: string