LU-5580 ptlrpc: policy switch directly in tbf

LU-5580 ptlrpc: policy switch directly in tbf

Former version can't change nid to jobid(or reversely) directly in
tbf, it need to change to FIFO(or any other policy) first. This patch
fix this problem. It save the policy argument(like "nid" in tbf),
and if the policy start with a new argument(like "jobid"), it will
stop the former policy and start a new one.

This is also adapt to any other nrs policies if they have arguments.

Signed-off-by: Wu Libin <lwu@ddn.com>
Change-Id: I645af94d774f60e2081e3716b2f249fcab4930d4
Reviewed-on: http://review.whamcloud.com/11749
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>