HBASE-7407 TestMasterFailover under tests some cases and over tests some others

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1445074 13f79535-47bb-0310-9956-ffa450edef68
HBASE-7789 Clean DeadServer.java and add a Jitter method in ConnectionUtils

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1445087 13f79535-47bb-0310-9956-ffa450edef68