merge-verify job failed on GC

add an mvn-opts:
-Xmx512m -XX:MaxPermSize=128m

Change-Id: Ib14d6437fbafec7b9992d86a64a23ae7565efe9a
Issue-ID: APPC-1711
Signed-off-by: Taka Cho <takamune.cho@att.com>
diff --git a/jjb/appc/appc-master.yaml b/jjb/appc/appc-master.yaml
index 30a4b94..01e65b2 100644
--- a/jjb/appc/appc-master.yaml
+++ b/jjb/appc/appc-master.yaml
@@ -4,6 +4,7 @@
     project-name: 'appc'
     jobs:
       - '{project-name}-{stream}-verify-java':
+          mvn-params: '-Xmx512m -XX:MaxPermSize=128m'
           build-node: ubuntu1604-builder-8c-8g
       - '{project-name}-{stream}-merge-java':
           build-node: ubuntu1604-builder-8c-8g