syslog: fixes and updates to rsyslogd and logrotate.
Adjust lograte size to prevent a mismatch.
Change rsyslogd size to be actual size instead of a naive value.
Potentially fix bug #13699000 by increasing the maximum number of TCP sessions.

Rsyslog was rejecting agents from connecting because of MaxSessions, which caused those
agents to go into spirals of trying to restart their rsyslog worker over and over,
which then generated tons of DEBUG level logging on machine-0 because of the workers
restarting, which then spammed the log file a lot.
[WIP] Support for filtering status on different criteria.

- From spec: https://docs.google.com/a/canonical.com/document/d/1olIjfnMIKPbNMmNBhfjwlnzdRvY-xBKygpIOhv7QIkE/edit#heading=h.tdsd6gcvc55e
Merge branch 'master' into rsyslog-max-connections-1369900

Small conflict that can be trivially fixed.

Conflicts:
	utils/syslog/config.go
Merge, refactoring, additional filters, tests.

- Merge branch 'master' into status-filtering.
- Filters moved into their own file.
- Now filtering machines as first-class objects.
- Filters broken down into atomic operations for re-usability.
- Meat of tests is now present.
Merge remote-tracking branch 'refs/remotes/origin/master' into status-filtering
Migration code for JobManageNetworking added, tests still missing.
Holistic unit-chain matching.

- Situations in which the entire chain of units and their subordinates do not match are now handled correctly.
Added reboot worker
respond to feedback
Respond to feedback
remove locks
cleanup
rebase and fix
Trace errors
initial commit
Added restore worker
Use state to determine restore mode now
Revert "Use state to determine restore mode now"

This reverts commit 5028a4fd6dd5015df437f7444a0e1d694e34237b.
Added restore watcher to the proper place