Configure G1GC in onos-service

Change-Id: I03a6c0fecd276d6a44b00573a108cb02462769d0
diff --git a/jjb/OnosSystemTest/onos-test-freestyle.yaml b/jjb/OnosSystemTest/onos-test-freestyle.yaml
index ac53ce8..592ab29 100644
--- a/jjb/OnosSystemTest/onos-test-freestyle.yaml
+++ b/jjb/OnosSystemTest/onos-test-freestyle.yaml
@@ -345,7 +345,7 @@
 
       - string:
          name: 'ONOSJAVAOPTS'
-         default: "\"${{JAVA_OPTS:--Xms8G -Xmx8G -Dkaraf.log.console=INFO -Dds.lock.timeout.milliseconds=60000}}\""
+         default: "\"${{JAVA_OPTS:--Xms8G -Xmx8G -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -Dkaraf.log.console=INFO -Dds.lock.timeout.milliseconds=60000}}\""
          description: 'onos cell JAVA_OPTS setting'
 
       - string: