HADOOP-10079. log a warning message if group resolution takes too long (cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.2@1538115 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5035. getFileLinkStatus and rename do not correctly check permissions of symlinks.  (Andrew Wang via Colin Patrick McCabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.2@1538121 13f79535-47bb-0310-9956-ffa450edef68