support the case where chef has already started a service but then it has been stopped out-of-band

if a user stops postgres at the machine, running the server recipe susequently fails -- it does not detect that the service is running (on standard opscode ubuntu vagrant box, using Chef 11.6)

note - this contains a "start the service via the shell" anti-pattern.  there may be a better way.  see the question at http://serverfault.com/questions/534498/how-to-ensure-a-service-is-running-using-chef