HBASE-3669 Region in PENDING_OPEN keeps being bounced between RS and master -- added some debugging

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1085066 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/hadoop/hbase/zookeeper/ZKAssign.java

@@ -694,7 +694,8 @@ public class ZKAssign {
       LOG.warn(zkw.prefix("Attempt to transition the " +
         "unassigned node for " + encoded +
         " from " + beginState + " to " + endState + " failed, " +
-        "the node existed but was in the state " + existingData.getEventType()));
+        "the node existed but was in the state " + existingData.getEventType() +
+        " set by the server " + existingData.getServerName()));
       return -1;
     }