HBASE-9029 Backport HBASE-8706 Some improvement in snapshot to 0.94 (Jerry He, original patch by Matteo)

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1509512 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8670 [0.94] Backport HBASE-8449,HBASE-8204 and HBASE-8699 to 0.94 (Refactor recoverLease retries and pauses)

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1509532 13f79535-47bb-0310-9956-ffa450edef68
HBASE-9107 [0.94] Backport HBASE-6950 TestAcidGuarantees system test now flushes too aggressively to 0.94

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1509533 13f79535-47bb-0310-9956-ffa450edef68
HBASE-9106 Do not fail TestAcidGuarantees for exceptions on table flush

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HBASE-9085 Integration Tests fails because of bug in teardown phase where the cluster state is not being restored properly. (gautam) 

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