LU-18272 build: remove Summary line from osd-zfs

LU-18272 build: remove Summary line from osd-zfs

Resolve spurious warning:
   warning: line 390: second Summary
when building src rpm:

Test-Parameters: trivial
HPE-bug-id: LUS-12538
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: I6aa591aae3ae4dc07a36740e12ef3520cea035ef
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56506
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: corey tesdahl <corey.tesdahl@hpe.com>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>