Results should use the MOID as a key, not the name

[jeking3]

In some commands like host_get, vm_guest_info_get, and vm_env_items_get the results are indexed by name. Since names can be ambiguous (more so for VMs than hosts), it would be better to index results by MOID, otherwise two VMs with the same name in different datacenters might bash over each-other in the results. Further, if someone does a lookup of a host or a VM by MOID, they want the result indexed by MOID.

In general one should encourage folks to use get_moid to resolve something's name to a MOID, and then use the MOID for the rest of the time. This eliminates ambiguity in results, and is especially important when making modifications to things (to make sure the correct object is being manipulated). I see there is already logic in inventory.py to check for multiple objects and raise an exception.