Rework default route handling to consolidate decisions in the policy,
	and to take active VPN connections into account when changing the default
	route (bgo #545912)

	* src/NetworkManager.c
		- (main): pass the vpn_manager to the policy so it knows about active
			VPN connections; clean up the named manager which wasn't done before

	* src/NetworkManagerPolicy.c
	  src/NetworkManagerPolicy.h
		- (nm_policy_new): get a clue about the vpn_manager
		- (update_default_route): remove, fold into update_routing_and_dns()
		- (update_routing_and_dns): handle active VPN connections too; an
			active VPN connection becomes the default route if it does not have
			server-specified or user-specified custom routes.  Otherwise, the
			best active device gets the default route
		- (vpn_connection_activated, vpn_connection_deactivated, nm_policy_new,
		   nm_policy_destroy): track VPN connection activation and deactivation
			and update the default route when appropriate

	* src/NetworkManagerSystem.c
	  src/NetworkManagerSystem.h
		- (nm_system_vpn_device_unset_from_ip4_config): remove, put functionality
			in the VPN connection itself
		- (nm_system_vpn_device_set_from_ip4_config,
		   nm_system_device_set_from_ip4_config): merge together to make
			nm_system_apply_ip4_config()
		- (add_vpn_gateway_route): add a route to the VPN's external gateway
			via the parent device
		- (nm_system_apply_ip4_config): simplify
		- (add_ip4_route_to_gateway): new function; add a direct route to the
			gateway if needed
		- (nm_system_device_replace_default_ip4_route): simplify, break gateway
			route stuff out into add_ip4_route_to_gateway() for clarity

	* src/nm-device.c
		- (nm_device_set_ip4_config): update for nm_system_apply_ip4_config()

	* src/vpn-manager/nm-vpn-connection.c
	  src/vpn-manager/nm-vpn-connection.h
		- (nm_vpn_connection_get_ip4_config, nm_vpn_connection_get_ip_iface,
		   nm_vpn_connection_get_parent_device): add
		- (nm_vpn_connection_ip4_config_get): make the requirement of a tunnel
			device explicit
		- (connection_state_changed): update the named manager now that
			nm_system_vpn_device_unset_from_ip4_config() is gone; do something
			useful on errors

	* src/vpn-manager/nm-vpn-manager.c
	  src/vpn-manager/nm-vpn-manager.h
		- Add a 'connection-activated' signal
		- (nm_vpn_manager_get_active_connections): new function; mainly for the
			policy to find out about active VPN connections



git-svn-id: http://svn-archive.gnome.org/svn/NetworkManager/trunk@4167 4912f4e0-d625-0410-9fb7-b9a5a253dbdc