Minijail: add logging for seccomp filter failures.

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

Change-Id: I16cdb8fbcf1cb13f2dee5521f97fb8d0bdbdf93b
Reviewed-on: https://gerrit.chromium.org/gerrit/29053
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Tested-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Commit-Ready: Jorge Lucangeli Obes <jorgelo@chromium.org>
12 files changed