LU-9710 utils: adjust barrier_stat input/output

LU-9710 utils: adjust barrier_stat input/output

The command format will be:
lctl barrier_stat [--state|-s] [--timeout|-t] <fsname>

If no option is specified, or both "state" and "timeout"
options are specified, then the output format will be:
state: xxx
timeout: nnn seconds

Otherwise, only the value ('xxx' or 'nnn') corresponding
to the given option will be printed.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: If39f95ef984be3ab709b1366fdefe8eedb4b2453
Reviewed-on: https://review.whamcloud.com/27810
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>