createNodesInGroup fails on GCE if there are existing instances which fail name validation

JClouds provisioning fails when we try to create nodes in a GCE project that has one or more existing instances with names of the format "ss-production" - where ss is any two letter string and production is any string.

These are valid instance names in GCE but fail JClouds validation - which seems to split on the hyphen and requires individual components to be greater than 3 characters.

A full stack trace is here:
https://gist.github.com/ssk2/853ba032135c60621a9a

I think the offending logic is in this method: https://github.com/jclouds/jclouds-labs-google/blob/master/google-compute-engine/src/main/java/org/jclouds/googlecomputeengine/compute/functions/InstanceInZoneToNodeMetadata.java#L82 - which iterates over all groups.

To fix, I think it'd be necessary to change how validation happens to validate on the entire name.