TestHASafeMode started failing on the
HDFS-3042 branch after the commit of HADOOP-8247. The reason is that testEnterSafeModeInANNShouldNotThrowNPE restarts the active node, and then tries to make an RPC to it right after restarting. The RPC picks up a cached connection to the old (restarted) NN, which causes an EOFException. This was just due to a test change that was made in HADOOP-8247, not due to any change made by the actual patch.