Fix bug in airplane mode.

If the phone comes up in airplane mode you and you turn it off,
you can currently end with both mobile and wifi turned on.

bug:2524413
Change-Id: I7a841c955be9038109d0b220070406a3fbd3e8e9
diff --git a/core/java/android/net/MobileDataStateTracker.java b/core/java/android/net/MobileDataStateTracker.java
index 22e4325..98f32b3 100644
--- a/core/java/android/net/MobileDataStateTracker.java
+++ b/core/java/android/net/MobileDataStateTracker.java
@@ -369,7 +369,11 @@
                 }
                 // else fall through
             case Phone.APN_TYPE_NOT_AVAILABLE:
-                mEnabled = false;
+                // Default is always available, but may be off due to
+                // AirplaneMode or E-Call or whatever..
+                if (mApnType != Phone.APN_TYPE_DEFAULT) {
+                    mEnabled = false;
+                }
                 break;
             default:
                 Log.e(TAG, "Error in reconnect - unexpected response.");