* Make propellor resistent to changes to shared libraries, such as libffi,
which might render the propellor binary unable to run. This is dealt with
by checking the binary both when running propellor on a remote host,
and by Cron.runPropellor. If the binary doesn't work, it will be rebuilt.
* Note that since a new switch had to be added to allow testing the binary,
upgrading to this version will cause a rebuild from scratch of propellor.
Joey Hess