VMware: Remove unnecessary deepcopy()s in test_configdrive

test_configdrive was doing a deepcopy of its test_instance object in
some tests. This was unnecessary, as the object is created fresh in
setUp().

Also, change a couple of dict lookups of test_instance to object
properties.

Change-Id: I3a5039fde9f8fba5285d90b28743b7af8cd1a168
Merge "VMware: Remove unnecessary deepcopy()s in test_configdrive"