Feature/batched values

allowStaleDatapoint is not a valid keyword argument to writeRRD() in Zenoss 4.1.1. So this will cause PythonCollector to fail on Zenoss 4.1.1. Look at how it was done in a backwards compatible way in vSphere.

https://github.com/zenoss/ZenPacks.zenoss.vSphere/commit/35251a8