[To dev/1.3] Fix SessionPool client leak on reconnection and query failures, and preserve server error messages#45

HTHou merged 2 commits intodev/1.3apache/iotdb-client-csharp:dev/1.3from

dev/1.3_fix_session_pool_leakapache/iotdb-client-csharp:dev/1.3_fix_session_pool_leakCopy head branch name to clipboard