LU-16707 scripts: update license-status

LU-16707 scripts: update license-status

Improve license-status script to parse SPDX text and
to only look at files tracked by git. This will make
it easier to track which files still need SPDX.

Test-Parameters: trivial
Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: I4ece6c7af6133d3e6fa0771dbf49bc511c5f853c
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50515
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>