handle empty dirs when migrating distdirs

If there are no files in the dir that match the glob, or there are
broken symlinks, don't try migrating them over.

BUG=None
TEST=CQ passes

Change-Id: I350680594b35d2df6065113afe0ce3447ee13e1f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2290711
Reviewed-by: Kalvin Lee <kdlee@chromium.org>
Tested-by: Kalvin Lee <kdlee@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
1 file changed