Fix AMR codec not enabled on old installations.

res/xml/preferences.xml

@@ -59,6 +59,7 @@
 				android:summary="@string/pref_ilbc_summary"/>
 			<CheckBoxPreference android:key="@string/pref_codec_amr_key" 
 				android:title="@string/pref_codec_amr" 
+				android:defaultValue="true"
 				android:shouldDisableView="true"  />
 		 	<CheckBoxPreference android:key="@string/pref_codec_gsm_key"
 				android:title="@string/pref_codec_gsm"/>

src/org/linphone/LinphoneManager.java

@@ -813,6 +813,7 @@ public final class LinphoneManager implements LinphoneCoreListener {
 		}
 	}
 
+	// Called on first launch only
 	public void initializePayloads() {
 		Log.i(TAG, "Initializing supported payloads");
 		Editor e = mPref.edit();