Don't allow renaming of domains by the backdoor

Don't allow renaming of domains by the backdoor

Several APIs allow for custom XML to be passed in. This is
checked for ABI stability, which will ensure the UUID is
not being changed. There isn't validation that the name
did not change though. This could allow renaming of guests
via the backdoor, which in turn could allow for bypassing
access control restrictions based on names.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>