SOLR-5577: Harden leaking Timer thread.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_6@1559589 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/solr/solrj/src/java/org/apache/solr/common/cloud/ConnectionManager.java b/solr/solrj/src/java/org/apache/solr/common/cloud/ConnectionManager.java
index 04113d0..d001d5f 100644
--- a/solr/solrj/src/java/org/apache/solr/common/cloud/ConnectionManager.java
+++ b/solr/solrj/src/java/org/apache/solr/common/cloud/ConnectionManager.java
@@ -84,6 +84,12 @@
         }
         
       }, (long) (client.getZkClientTimeout() * 0.90));
+      if (isClosed) {
+        // we might have closed after getting by isClosed
+        // and before starting the new timer
+        disconnectedTimer.cancel();
+        disconnectedTimer = null;
+      }
     }
     connected = false;
     notifyAll();