HBASE-10537 Let the ExportSnapshot mapper fail and retry on error

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1569680 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10523 Correct wrong handling and add proper handling for swallowed InterruptedException thrown by Thread.sleep in util (Feng Honghua)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1569733 13f79535-47bb-0310-9956-ffa450edef68