allow concurrent job for opencontrail test

Change-Id: I98376b8c7f836bc44bf1f1da4a598303ef5fb67b
diff --git a/jenkins/client/job/opencontrail/build/test.yml b/jenkins/client/job/opencontrail/build/test.yml
index 8ad7d95..d26e56e 100644
--- a/jenkins/client/job/opencontrail/build/test.yml
+++ b/jenkins/client/job/opencontrail/build/test.yml
@@ -36,7 +36,7 @@
              artifact:
                keep_num: 5
             type: workflow-scm
-            concurrent: false
+            concurrent: true
             quiet_period: 120
             scm:
               type: git