restore file contexts for dev and test image.

Dev and test image has more files being installed, or modified later
than base_image_util restores the file contexts.

We need to restore SELinux file contexts every time we modify an image
to make sure all files have their contexts correct.

BUG=b:112616150
TEST=build_image

Change-Id: Ie8b7a2684ec48dc7a10ac3f63f546b895faa20d2
Reviewed-on: https://chromium-review.googlesource.com/1174587
Commit-Ready: Qijiang Fan <fqj@google.com>
Tested-by: Qijiang Fan <fqj@google.com>
Reviewed-by: Kenny Root <kroot@google.com>
5 files changed