HBASE-8864 Fix 2 javadoc warnings (Ted Yu)



git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.95@1501083 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8882 Addendum to add category to IntegrationTestMTTR.

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.95@1501085 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8895 Misc: replace hbase.client.retries.number w/ define and remove unused imports

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.95@1501088 13f79535-47bb-0310-9956-ffa450edef68