The return code of "service pf onestatus" is usually zero on FreeBSD (tested with FreeBSD 10.0), even if pf is not running. So the service module always thinks that pf is running, even when it needs to be started.
* Use the newly added 'default' argument to know if the default flags are set
or not.
* Handle that 'status' may either return flags or YES/NO.
* Centralize flag handling logic.
* Set action variable after check if we need to keep going.
Big thanks to @ajacoutot for implementing the rcctl 'default' argument.
* Make the module support enable/disable of special services like pf via rcctl.
Idea and method from @jarmani.
* Make the module handle when the user supplied 'arguments' variable does not
match the current flags in rc.conf.local.
* Update description now that the code tries to use rcctl for everything if it
is available.
Based on input from @jarmani:
* A return value of 2 now means a service does not exist. Instead of
trying to handle the different meanings of rc after running "status",
just look at stderr to know if something failed.
* Skip looking at stdout to make the code cleaner. Any errors should
turn up on stderr.
