MAPREDUCE-4374. Merging change r1502048 from branch-2 to branch-2.1-beta.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502054 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5333. Add test that verifies MRAM works correctly when sending requests with non-normalized capabilities. (ywskycn via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502063 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9661. Allow metrics sources to be extended. (sandyr via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502064 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9355.  Abstract symlink tests to use either FileContext or FileSystem.  (Andrew Wang via Colin Patrick McCabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502065 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9673.  NetworkTopology: when a node can't be added, print out its location for diagnostic purposes.  (Colin Patrick McCabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502066 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9414.  Refactor out FSLinkResolver and relevant helper methods. (Andrew Wang via Colin Patrick McCabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502067 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9416.  Add new symlink resolution methods in FileSystem and FileSystemLinkResolver.  (Andrew Wang via Colin Patrick McCabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502068 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4797. BlockScanInfo does not override equals(..) and hashCode() consistently.  (szetszwo)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502069 13f79535-47bb-0310-9956-ffa450edef68
YARN-866. Add test for class ResourceWeights. (ywskycn via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502071 13f79535-47bb-0310-9956-ffa450edef68
YARN-736. Add a multi-resource fair sharing metric. (sandyr via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502072 13f79535-47bb-0310-9956-ffa450edef68
YARN-883. Expose Fair Scheduler-specific queue metrics. (sandyr via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1502073 13f79535-47bb-0310-9956-ffa450edef68