LU-18086 sec: do not allocate empty pools

LU-18086 sec: do not allocate empty pools

If the node does not have enough memory, we might end up allocating
empty pools at some orders. Prevent empty pools as they are useless
and the rest of the code expect valid pools.

Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I9c5d9eeb557df0c91efecd6871654d1e48e5662a
Reviewed-by: Sergey Cheremencev <scherementsev@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56271
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>