HDFS-4880. Print the image and edits file loaded by the namenode in the logs. Contributed by Arpit Agarwal.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1490746 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-xxx-hadoop-auth-kerberos-realm-trunk-gd