Alternate method to find compute resource to include cluster computer resources

find_compute_resource only finds VIM::ComputeResource
unrolled find_compute_resource to allow for ComputeResource or ClusterComputeResource
RbVmomi parser error with ClusterComputeResource, workaround handling exception and using alternate method to find childEntity in the folder.
Did you see Rbvmomi has a new maintainer? You can raise dependency to version 1.8.2 if it helps.