dev_image: make sure /usr/lib/debug is a symlink

If /usr/lib/debug exists and is a dir, then the symlink operation will
create a "debug" symlink under there leading to /usr/lib/debug/debug/.
This makes no sense, so fail if we can't create a symlink exactly at
/usr/lib/debug.

BUG=chromium:924355
TEST=precq passes and /usr/lib/debug is a symlink in the dev image
CQ-DEPEND=CL:924355

Change-Id: I151e942c34d04d2e5b0f48eecbda72c65f5309ed
Reviewed-on: https://chromium-review.googlesource.com/1480438
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Alex Klein <saklein@chromium.org>
1 file changed