KCC: Don't pretend to "load_all_transports"

KCC: Don't pretend to "load_all_transports"

Samba doesn't do SMTP, so nor does Samba KCC. Because we were
following the spec, we have had special cases for non-IP transports
in numerous places. This removes a few more of those.

The gains are a loss of complexity and the removal of untestable code.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Conflicts:
	python/samba/kcc/__init__.py