HADOOP-3511. Namenode should not restore the root's quota if the quota was not saved in the image. Contributed by Hairong Kuang.

Files:
modified: /hadoop/core/trunk/src/java/org/apache/hadoop/dfs/FSImage.java (try)
modified: /hadoop/core/trunk/src/java/org/apache/hadoop/dfs/QuotaExceededException.java (try)
modified: /hadoop/core/trunk/CHANGES.txt (try)