Fix is_go_service_running()

Because of the backticks, the if-block will fail 
because "PID" in the ps output is not a command.
Address 2 issues: start() and stop()

* in start(), add a is_go_service_running check prior to
  starting the app. This is needed because the return status
  check does not work for backgrounding job; in the end the
  PID file gets clobbered.
* in stop(), the $ret check is testing for success instead
  of failure for retries.
Merge pull request #3 from dvusboy/master

Fix is_go_service_running()