[shill] Make IPConfig objects have sane DBus Paths

following the following schema: /ipconfig/<devicename>_<per-run serial number>_<config type>

BUG=chromium-os:17744
TEST=unit, run on device and use /usr/local/lib/flimflam/list-devices

Change-Id: Ia88814d46facce525d866c8309556131d8fb6a0d
Reviewed-on: http://gerrit.chromium.org/gerrit/4535
Tested-by: Chris Masone <cmasone@chromium.org>
Reviewed-by: Darin Petkov <petkov@chromium.org>
diff --git a/dhcp_config.cc b/dhcp_config.cc
index b3605be..8e9e7ff 100644
--- a/dhcp_config.cc
+++ b/dhcp_config.cc
@@ -22,6 +22,7 @@
 
 namespace shill {
 
+// static
 const char DHCPConfig::kConfigurationKeyBroadcastAddress[] = "BroadcastAddress";
 const char DHCPConfig::kConfigurationKeyDNS[] = "DomainNameServers";
 const char DHCPConfig::kConfigurationKeyDomainName[] = "DomainName";
@@ -38,13 +39,15 @@
 const char DHCPConfig::kReasonRebind[] = "REBIND";
 const char DHCPConfig::kReasonReboot[] = "REBOOT";
 const char DHCPConfig::kReasonRenew[] = "RENEW";
+// static
+const char DHCPConfig::kType[] = "dhcp";
 
 
 DHCPConfig::DHCPConfig(ControlInterface *control_interface,
                        DHCPProvider *provider,
                        const string &device_name,
                        GLib *glib)
-    : IPConfig(control_interface, device_name),
+    : IPConfig(control_interface, device_name, kType),
       provider_(provider),
       pid_(0),
       child_watch_tag_(0),