HDFS-5504. In HA mode, OP_DELETE_SNAPSHOT is not decrementing the safemode threshold, leads to NN safemode. Contributed by Vinay.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1541773 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5487. Introduce unit test for TokenAspect. Contributed by Haohui Mai.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1541776 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HDFS-4312-trunk-gd