Minijail: extract utility functions.

Extract utility functions and add them, together with logging,
to a separate util.(c|h) file.

BUG=chromium-os:33361
TEST=unit tests
TEST=security_Minijail0, security_Minijail_seccomp, platform_CrosDisksArchive.

Change-Id: Ied436a7b27f14ef87198b7bf007634b28cbbd480
Reviewed-on: https://gerrit.chromium.org/gerrit/29492
Tested-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Reviewed-by: Elly Jones <ellyjones@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Commit-Ready: Jorge Lucangeli Obes <jorgelo@chromium.org>
7 files changed