[Tools] support set_flag_for_all in tserver use optional parameter 'force'.

This patch adds support for the command `kudu tserver set_flag_for_all`
using --force flag.

Change-Id: I716c2a8be4a6041aa28b5191b55022158536d97c
Reviewed-on: http://gerrit.cloudera.org:8080/19243
Tested-by: Kudu Jenkins
Reviewed-by: Alexey Serbin <alexey@apache.org>
2 files changed