[1118091] RHQ Agent resources are not being auto-clustered in resource group due to their unique resource keys

To enable good autoclustering of RHQ Agent resources across platforms the
agent resource keys must be the same.  In general each platform has at most
one imported 'RHQ Agent' child resource and it is named the same as the
platform (Actually the platform's resource key). In this case do not
incorporate the agent name into the resource key.  In that way we can have
a generic static reskey for the agents, across platforms, while still
maintaining unique agent names across all agents (an RHQ requirement).  In
the rare case that a platform has multiple agents deployed (typically a
perftest scenario, but sometimes a production scenario) at most one agent
will get assigned the static key, only the one whose name matches the
parent.  All others will get the *predictable* legacy keys we've used up to
this point.  So, in the vast majority of cases, we should see good
auto-clustering of the rhq agents.