Since we enforce the fact that bond, bridge, team, and vlan
interface-name properties match NMSettingConnection:interface-name,
nm_connection_get_virtual_iface_name() can be replaced with
nm_connection_get_interface_name() basically everywhere.

The one place this doesn't work is with InfiniBand partitions (where
get_virtual_iface_name() was actually computing the name), but for the
most part we only need to care about the interface names of InfiniBand
partitions in places where we also already need to do some other
InfiniBand-specific handling as well, so we can use an
InfiniBand-specific method
(nm_setting_infiniband_get_virtual_interface_name()) to get it.

(Also, while updating nm_device_get_virtual_device_description(), fix
it to handle InfiniBand partitions too.)