manager: relax check when creating virtual devices

For each connection that corresponds to a software device, we create a
"unrealized" device that then becomes realized just before the
connection starts activating. Currently, in certain conditions NM
creates two devices with the same name and type, one realized and one
not; this is not expected and can lead to other issues especially when
a software device is reactivated.

Avoid that by relaxing the check in system_create_virtual_device(): if
a device exists with the same name and type, we don't want to create
another even if the type-specific parameters differ.

src/core/nm-manager.c

@@ -2549,7 +2549,7 @@ system_create_virtual_device(NMManager *self, NMConnection *connection)
 
     /* See if there's a device that is already compatible with this connection */
     c_list_for_each_entry (dev_candidate, &priv->devices_lst_head, devices_lst) {
-        if (nm_device_check_connection_compatible(dev_candidate, connection, TRUE, NULL)) {
+        if (nm_device_check_connection_compatible(dev_candidate, connection, FALSE, NULL)) {
             if (nm_device_is_real(dev_candidate)) {
                 _LOG3D(LOGD_DEVICE, connection, "already created virtual interface name %s", iface);
                 return NULL;