Fix TTS engine checkbox click handler

Before, the dialog asking whether to really enable
the engine wasn't shown. Also, the Default engine
list was not refreshed until you left the TTS settings
and came back.

Change-Id: I8cbded0fe9eedbfb05c294d831c91a857349b224

src/com/android/settings/TextToSpeechSettings.java

@@ -182,6 +182,7 @@ public class TextToSpeechSettings extends SettingsPreferenceFragment implements
                 prefKey = KEY_PLUGIN_ENABLED_PREFIX + engineName;
                 enablePref.setKey(prefKey);
                 enablePref.setTitle(engine.label);
+                enablePref.setOnPreferenceClickListener(this);
                 mEnginesGroup.addPreference(enablePref);
             }
             if (engineHasSettings(engineName)) {