VMware: create utility functions

The following method has been moved to utility functions:
 - _get_values_from_object_properties

This is now in the vm_util module and is called:
 - get_values_from_object_properties

In addtion to this _get_diagnostic_from_object_properties
has been dropped and the code using that method now leverages
get_values_from_object_properties.

This is related to the blueprint vmware-spawn-refactor.

Change-Id: I5033cae8838179b4c1ace327a42dc626493f19e8
Merge "VMware: create utility functions"