fastbulk - Exit w/success on more conditions

fastbulk - Exit w/success on more conditions

* If the binary package build succeeds but the pkg_add fails it is likely
  due to an install conflict.  Exit w/success for this case (since our goal
  is to generate the binary package, we succeeded!).

* Do an early check to see if the binary package has already been built
  and exit immediately if it has.