Don't die() on bind mounts.

By the time we get to the removed lines, |mounts_head| will be valid
in the parent (Minijail) process, but |flags.chroot| and
|flags.pivot_root| will have been cleared by minijail_preexec().
The removed lines were then incorrectly aborting the process too early.

The flags *will* be set in the minijail struct used by the
child (jailed) process, so the bind mounts will happen correctly.

A follow-up CL will make sure |mounts_head| is never valid when
both flags are cleared, so that we can correctly check for this.

While in there, fix a comment and an info() message.

security_Minijail0 now passes.

Bug: 25368607
Change-Id: I5ac85ee62560ba8957bdab3fc84689ed06d106f0
2 files changed