Catch exception on Thrift client close()

Thrift's close() may call flush(), which calls write(), which may
throw. This patch catches that exception, logs and then ignores it.

Change-Id: I4952de1836531671546676ede40456e391b7c0d5
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4214
Reviewed-by: Daniel Hecht <dhecht@cloudera.com>
Tested-by: Henry Robinson <henry@cloudera.com>