LU-11743 utils: allow lctl pool_list on separate MGS

Change lctl pool_list command 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.

Also, those test scripts from the patch of LU-9899 to mount a client
on the standalone MGS to allow OST pools to work properly are cleared.

Change-Id: Ic25931d49c2cf747da2a3f2ac3c25a21f6878991
Test-Parameters: standalonemgs=true testlist=ost-pools.sh,sanity.sh,conf-sanity.sh
Signed-off-by: Emoly Liu <emoly@whamcloud.com>
Signed-off-by: Vladimir Saveliev <c17830@cray.com>
Reviewed-on: https://review.whamcloud.com/35895
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>