Add ctr_id_short to Audit log

[TomSweeneyRedHat]

Signed-off-by: TomSweeneyRedHat tsweeney@redhat.com Audit logging was not showing the containers id. Unlike docker-1.12.6, the audit middleware is being initialized appropriately in this version and dockerd/daemon.go did not need to be fixed. This change only adds the short container id to the audit log.

This addresses https://bugzilla.redhat.com/show_bug.cgi?id=1496176

What I did
I've added a 'ctr_id_short' field to the audit logging and a couple of debug messages.

How I did it
Changed the code and lots of testing.

How to verify it

The old audit log entries looked like:

type=VIRT_CONTROL msg=audit(1512770060.628:254): pid=1768 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:container_runtime_t:s0 msg='op=attach vm-pid=? auid=0 hostname=? reason=api vm=? user=root exe=? exe="/usr/bin/dockerd-current" hostname=? addr=? terminal=? res=success'

The new ones look like:

type=VIRT_CONTROL msg=audit(1515610710.130:485): pid=19793 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:container_runtime_t:s0 msg='reason=api auid=0 exe=sleep hostname=8386cb7735f4 ctr_id_short=8386cb7735f4 op=attach vm=centos vm-pid=0 user=root exe="/usr/bin/dockerd-current" hostname=? addr=? terminal=? res=success'

Note the addition of the ctr_id_short field and the appropriate values in the vm, vm-pid, exed and other fields.

Description for the changelog
Correct audit logging for container operations.

[TomSweeneyRedHat]

@jwhonce @rhatdan @runcom ptal

Addresses https://bugzilla.redhat.com/show_bug.cgi?id=1496176

[rhatdan]

LGTM

[TomSweeneyRedHat]

@rhatdan @runcom Can this be merged? If not, please let me know what (if anything) I can do. This will address https://bugzilla.redhat.com/show_bug.cgi?id=1496176 which is on the 7.5 blocker list.

[rhatdan]

I will merge.

[rhatdan]

Ask @lsm5 and franticek to rebuild.