Allow concurrent build for oc

Change-Id: I9e4568b584fb0ff78f576094618273bf54914d23
diff --git a/jenkins/client/job/opencontrail/build/generic.yml b/jenkins/client/job/opencontrail/build/generic.yml
index 81e2743..7cd226e 100644
--- a/jenkins/client/job/opencontrail/build/generic.yml
+++ b/jenkins/client/job/opencontrail/build/generic.yml
@@ -56,7 +56,7 @@
              artifact:
                keep_num: 5
             type: workflow-scm
-            concurrent: false
+            concurrent: true
             quiet_period: 120
             scm:
               type: git