EX-9054 lipe: fix incorrect pool pointer usage

EX-9054 lipe: fix incorrect pool pointer usage

Use pointer to pool struct instead of pool name.

Fixes: 504b0b0b61 (EX-9054 lipe: Add SSH stats per agent)
Test-Parameters: trivial testlist=hot-pools
Signed-off-by: Alexandre Ioffe <aioffe@ddn.com>
Change-Id: I436aaa2ea9eb0059c5cee00882fe4332c6e22fe5
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/55096
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>