JCLOUDS-607: ComputeService.createNodesInGroup throws NPE on FloatingIPA...

Addresses possible returned null value from 'FloatingIPApi.create()'. If upon check we find null then throw InsufficientResourcesException. This in turn will make a second check at IP allocation by iterating through 'FloatingIPApi.list()' and grabbing an available IP. If this subsequent call fails then re-throw InsufficientResourcesException.
It does NOT get turned into a RunNodesException higher up as it fails before the point the RNE is created (which happens in BaseComputeService around line 222). Let me play around a bit and see what I can make happen. I still think this is the right exception to throw but we should be able to capture it and embed it within an RNE.

As far as putting code out to a method: doing that now ;)