AMBARI-1106. User-specified custom configs (such as hdfs-site.xml overrides) should be persisted to maintain what the user specified. (Jaimin Jetly via yusaku)

git-svn-id: https://svn.apache.org/repos/asf/incubator/ambari/trunk@1431779 13f79535-47bb-0310-9956-ffa450edef68