Fix displaying of Data Roaming information.

The variable currentTab was set to 0 instead of the current tab if
nothing had changed.

bug: 18837275
Change-Id: Ic932a077129f644a18b6d5e45875b51438956318
diff --git a/src/com/android/phone/MobileNetworkSettings.java b/src/com/android/phone/MobileNetworkSettings.java
index e6b066b..b60c963 100644
--- a/src/com/android/phone/MobileNetworkSettings.java
+++ b/src/com/android/phone/MobileNetworkSettings.java
@@ -125,6 +125,7 @@
     private MyHandler mHandler;
     private boolean mOkClicked;
 
+    // We assume the the value returned by mTabHost.getCurrentTab() == slotId
     private TabHost mTabHost;
 
     //GsmUmts options and Cdma options
@@ -333,7 +334,7 @@
             }
             case DO_NOTHING: {
                 if (DBG) log("initializeSubscriptions: DO_NOTHING");
-                currentTab = 0;
+                currentTab = mTabHost != null ? mTabHost.getCurrentTab() : 0;
                 break;
             }
         }