LU-16390 tests: check Lustre filefrag in sanity-flr/49a

LU-16390 tests: check Lustre filefrag in sanity-flr/49a

Check that a Lustre-patched filefrag is installed when running
sanity-flr test_49a.

Lustre-change: https://review.whamcloud.com/49386
Lustre-commit: 37f18670e49b8150170f9b724b5f7089fa176c4e

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: Ic909ea4ca160d47480004f53a96ce7539ce5076c
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56605
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Deiter <adeiter@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>