mod_test_image_for_staging.sh: inline sudo_append

No other script uses this func anymore, so pull it out of common.sh.

BUG=None
TEST=None

Change-Id: Ib2901c30b90554f993a616cf2bd8769e4ad66cea
Reviewed-on: https://chromium-review.googlesource.com/1762461
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
1 file changed