LU-17000 utils: Use ssize_t to store return from sysconf()

LU-17000 utils: Use ssize_t to store return from sysconf()

Use ssize_t instead of size_t to capture return
from sysconf() as it can return a negative value

Test-Parameters: trivial testlist=sanity-flr
CoverityID: 414674 ("Unsigned compared against 0")
CoverityID: 414673 ("Unsigned compared against 0")
CoverityID: 414672 ("Unsigned compared against 0")
CoverityID: 414671 ("Unsigned compared against 0")
CoverityID: 414670 ("Unsigned compared against 0")
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CoverityID: 414668 ("Unsigned compared against 0")
CoverityID: 414667 ("Unsigned compared against 0")
Fixes: b02a9bc1 (LU-17000 utils: Add check after calling sysconf(_SC_PAGESIZE))
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: I03f280f25beb7b6b8b41888c379b0709a6195d9c
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/53936
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Timothy Day <timday@amazon.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>