strip_package.py should fail if the package was not installed

BUG=chromium:314132
TEST=remote trybots

Change-Id: I0badb73e8ecb5926389daddc72c356cc8d49c42a
Reviewed-on: https://chromium-review.googlesource.com/176268
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Yu-Ju Hong <yjhong@chromium.org>
Tested-by: Yu-Ju Hong <yjhong@chromium.org>
1 file changed