B #310: do not delete iface configuration

when {IFACE}_METHOD=skip in the contextualization

src/etc/one-context.d/loc-10-network.d/functions

@@ -61,6 +61,8 @@ initialize_network()
     _iface_mac=$(get_interface_mac)
 
     for _iface in $_context_interfaces; do
+        setup_iface_vars "$_iface"
+        skip_interface && continue
         _mac=$(get_iface_var "${_iface}" "MAC")
         _dev=$(get_dev "${_iface_mac}" "${_mac}")
 
@@ -606,4 +608,4 @@ get_onegate_ip() {
 
 missing_onegate_proxy_route() {
     is_link_local "$onegate_host" && [[ $onegate_proxy_route_missing == "yes" ]]
-}
+}