Enable the call setting when the VoIP feature is supported.

If the VoIP feature is included, the user need to be able to
configure the internet call settings even if it is in airplan mode.

Change-Id: I00d73fb0d9213162b8a9887cad0f800418446787
diff --git a/src/com/android/settings/Settings.java b/src/com/android/settings/Settings.java
index 5309cf5..b37c340 100644
--- a/src/com/android/settings/Settings.java
+++ b/src/com/android/settings/Settings.java
@@ -16,6 +16,7 @@
 
 package com.android.settings;
 
+import android.net.sip.SipManager;
 import android.os.Bundle;
 import android.preference.Preference;
 import android.preference.PreferenceActivity;
@@ -51,7 +52,9 @@
     @Override
     protected void onResume() {
         super.onResume();
-        findPreference(KEY_CALL_SETTINGS).setEnabled(!AirplaneModeEnabler.isAirplaneModeOn(this));
+        findPreference(KEY_CALL_SETTINGS).setEnabled(
+                !AirplaneModeEnabler.isAirplaneModeOn(this)
+                || SipManager.isVoipSupported(this));
     }
 
 }