Move restore logic to container instance

Change-Id: I1f940512adc71c2a3c738828c2fccf7cf6853652
Liberate access to resources hash

Change-Id: I62da2cd4b5f9a1b04ea25cbeb22a222f91e06517
Keep track of net_in/net_out in container snapshot

Change-Id: Ibe43679d54b4f5cd34c6aae197f8d70be62e4467
Always recover container snapshots

This used to only take place when the warden server was properly
drained. In reality, it is more likely that is is NOT properly drained
and just gets killed.

This commit doesn't cover every edge case but it a first attempt in
making this happen. Things that need to be checked/put in place are:

- The OOM notifier must run after recovery
- Memory limits must be persisted to and recovered from the snapshot
- Bandwidth limits must be persisted to and recovered from the snapshot
- The disk quota must be persisted to and recovered from the snapshot

Change-Id: I0d4fed1af58723d5f33c6be107f0cc2db999db19
Merge branch 'master' into snapshot-restore

Conflicts:
	warden/lib/warden/container/linux.rb
Add tmp directory to insecure skeleton
Fix tests

The stdout/stderr fields are no longer part of the job snapshot.
Rename netmask -> pooled_netmask for clarity

The previous implementation didn't return the right netmask for exactly
this reason.
Refactor oom.c to use select(2)
Make oom process die when parent dies
Make port pool configurable
Log configuration on start
Restart oom notifier on restore
Test that wshd isn't killed when warden is killed
Move all snapshot related logic to base.rb
Be more specific in matching errors
Set active state in after create
Remove obsoleted dirty_snapshot_marker code
Destroy containers than cannot be recovered
Test that a container is alive before restoring it