Description: If mysql_stmt_close() encountered error,
             it recorded error in prepared statement
             but then frees memory assigned to prepared
             statement. If mysql_stmt_error() is used
             to get error information, it will result
             into use after free.

             In all cases where mysql_stmt_close() can
             fail, error would have been set by
             cli_advanced_command in MYSQL structure.

Solution: Don't copy error from MYSQL using set_stmt_errmsg.
          There is no automated way to test the fix since
          it is in mysql_stmt_close() which does not expect
          any reply from server.
Reviewed-By: Georgi Kodinov <georgi.kodinov@oracle.com>
Reviewed-By: Ramil Kalimullin <ramil.kalimullin@oracle.com>