LU-16232 script: fix the argument parse

LU-16232 script: fix the argument parse

The issue makes script skip other arguments if
the special parameter is not last one.

Test-Parameter: trival

Fixes: b533700add (LU-16232 scripts: changelog/updatelog emergency cleanup)
Signed-off-by: Yang Sheng <ys@whamcloud.com>
Change-Id: Ia309e7b6f1a62e76b80851848601c3d0b03be8b2
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50876
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Mikhail Pershin <mpershin@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>