LU-11743 utils: allow lctl pool commands on separate MGS

LU-11743 utils: allow lctl pool commands on separate MGS

The current lctl code checks for the presence of configured pools on
the client and MDS via /proc or /sys files.  However, the MGS does
not parse the client/MDS configuration logs, so it does not create
the various files for the pools, which causes the pool commands to
fail verification.

Change lctl pool_new, pool_add, pool_remove and pool_destroy commands
to parse the configuration log directly when run on a standalone MGS
node.  This also allows the pool commands to be run when only the MGS
is started.

Test-Parameters: standalonemgs=true testlist=ost-pools.sh
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Signed-off-by: Emoly Liu <emoly@whamcloud.com>
Change-Id: Ib6fdb367c919f7b726fbf551dcfa6015593ebbe5
Reviewed-on: https://review.whamcloud.com/34110
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>