call phone.getGroupIdLevel2 to get gid2 for carrier identifier.

Bug: b/21078450
Change-Id: Ia4fb0f9b658c2d95e8621681cc7fc6ac25342142
diff --git a/src/com/android/phone/CarrierConfigLoader.java b/src/com/android/phone/CarrierConfigLoader.java
index abe05f8..9fbd4a4 100644
--- a/src/com/android/phone/CarrierConfigLoader.java
+++ b/src/com/android/phone/CarrierConfigLoader.java
@@ -62,7 +62,6 @@
 /**
  * CarrierConfigLoader binds to privileged carrier apps to fetch carrier config overlays.
  * TODO: implement persist cache
- * TODO: add gid2 to phone
  * TODO: handle package install/uninstall events
  */
 
@@ -285,7 +284,7 @@
         if (phone != null) {
             imsi = phone.getSubscriberId();
             gid1 = phone.getGroupIdLevel1();
-            // add gid2 after phone supports it.
+            gid2 = phone.getGroupIdLevel2();
         }
 
         return new CarrierIdentifier(mcc, mnc, spn, imsi, gid1, gid2);