dev_install: Correctly fetch package.provided

package.provided lives under etc/portage/profile instead of root
directory. Also fix a bug for the return code of curl command.

BUG=chromium:271959
TEST=Run 'dev_install --yes --reinstall' on a Link device. Verify
the content is correct in:
/usr/local/etc/portage/make.profile/package.provided/gsutil_provided

Change-Id: I1ab7400d7ca116509c2ea42c791ae80fdd9fa015
Reviewed-on: https://chromium-review.googlesource.com/65826
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Tested-by: Hsinyu Chao <hychao@chromium.org>
Commit-Queue: Hsinyu Chao <hychao@chromium.org>
1 file changed