PULSAR_PATH replaced with pulsar's path

Sorry for being so late with this...

It's a bloody simple change, just replace the string in the command we get from the queue. It passes tests fully, and seems to work in my testing instance.

- 10 minutes to fix
- 70 minutes before I figured out that adding in the other dependencies (https://github.com/galaxyproject/pulsar/issues/25) was causing failed builds. The multiple tracebacks in the travis reports really threw me for a loop.