Only show emergency app preference if enabled

Bug: 21471480
Change-Id: I93e5dcb9acb8be1220d2874d5bca764819139760
diff --git a/src/com/android/settings/applications/DefaultEmergencyPreference.java b/src/com/android/settings/applications/DefaultEmergencyPreference.java
index 2bda0ed..0062625 100644
--- a/src/com/android/settings/applications/DefaultEmergencyPreference.java
+++ b/src/com/android/settings/applications/DefaultEmergencyPreference.java
@@ -139,7 +139,8 @@
     }
 
     public static boolean isCapable(Context context) {
-        return context.getResources().getBoolean(
+        return TelephonyManager.EMERGENCY_ASSISTANCE_ENABLED
+                && context.getResources().getBoolean(
                 com.android.internal.R.bool.config_voice_capable);
     }