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.
Merge branch 'master' into rsyslog-max-connections-1369900

Small conflict that can be trivially fixed.

Conflicts:
	utils/syslog/config.go
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
Go fmted
Change Login Validator for one including restore
Small changes after @natefinch comments
Corrected Annotate used instead of Annotatef
added check and tests to stop add-units earlier if the destination machine doesn't exist, lp:1384732