HBASE-8946 Add a new function to Thrift 2 to open scanner, get results and close scanner (Hamed Madani)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1505290 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8948 Bound table pool size in Thrift 2 server

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1505321 13f79535-47bb-0310-9956-ffa450edef68