HACK, DO NOT SHIP: kernel update (debug umount issue)

Either cherry-pick for A/B build, or revert before shipping,
or take next kernel (which has the revert in it).

3ed3cdb HACK, DO NOT SHIP: Debug unmounting issue

Bug: 16378004
Change-Id: If0929514e4faa47d37d7c4c6c4f4d7019d93235f
1 file changed