network: Remove team support

It will be supported by Cockpit in the near future:
https://github.com/cockpit-project/cockpit/issues/4330

https://bugzilla.gnome.org/show_bug.cgi?id=747443

panels/network/connection-editor/net-connection-editor.c

@@ -581,9 +581,6 @@ typedef struct {
 
 static const NetConnectionType connection_types[] = {
         { N_("VPN"), nm_setting_vpn_get_type },
-#ifdef HAVE_NM_UNSTABLE
-        { N_("Team"), nm_setting_team_get_type },
-#endif /* NM_UNSTABLE */
         { N_("VLAN"), nm_setting_vlan_get_type }
 };
 static const NetConnectionType *vpn_connection_type = &connection_types[0];