shill: Update properties of all interfaces when creating a Cellular device.

The CL modifies Modem::CreateDeviceFromModemProperties to update
properties of all modem interfaces (e.g. Modem, Modem.Modem3gpp, etc)
instead of the Modem interface when creating a Cellular device instance.
This ensures that the created Cellular device has the correct
registration states.

BUG=chromium-os:34882
TEST=Tested the following:
1. Build and run unit tests.
2. Run network_3GModemControl.no-autoconnect test on Gobi 3000 and
   Icera Y3400 modem.

Change-Id: I49f9d216abded5ae0baa019df81fbbebcd134f57
Reviewed-on: https://gerrit.chromium.org/gerrit/34300
Commit-Ready: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Darin Petkov <petkov@chromium.org>
diff --git a/modem_manager_unittest.cc b/modem_manager_unittest.cc
index 3166e1e..9d5f532 100644
--- a/modem_manager_unittest.cc
+++ b/modem_manager_unittest.cc
@@ -313,11 +313,11 @@
   static DBusObjectsWithProperties GetModemWithProperties() {
     DBusPropertiesMap o_fd_mm1_modem;
 
-    DBusInterfaceToProperties i_to_p;
-    i_to_p[MM_DBUS_INTERFACE_MODEM] = o_fd_mm1_modem;
+    DBusInterfaceToProperties properties;
+    properties[MM_DBUS_INTERFACE_MODEM] = o_fd_mm1_modem;
 
     DBusObjectsWithProperties objects_with_properties;
-    objects_with_properties[kModemPath] = i_to_p;
+    objects_with_properties[kModemPath] = properties;
 
     return objects_with_properties;
   }