HBASE-10897 On master start, deadlock if refresh UI

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1584091 13f79535-47bb-0310-9956-ffa450edef68
Add link to Nick's blockcache series

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1584104 13f79535-47bb-0310-9956-ffa450edef68