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

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1509534 13f79535-47bb-0310-9956-ffa450edef68
HBASE-9085 Integration Tests fails because of bug in teardown phase where the cluster state is not being restored properly. (gautam) 

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1509540 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/0.94' into 0.94-gd