Enhance change default SMS app dialog to show list of apps

Settings shows a dialog to android.provider.Telephony.ACTION_CHANGE_DEFAULT
intent to confirm if user wants to change default SMS app to a new one.
This is used by SMS apps to obtain default status. In the opposite direction,
i.e. giving up default status, SMS apps have to bring up the wireless
settings page where the default SMS app setting was originally located.
MNC moved this setting to a different location therefore broke the
function. This change enhances the SmsDefaultDialog to display a list of
SMS apps so that user can choose a different default SMS app, when the
new default SMS app package name is not specified within the above
intent.

b/20430567

Change-Id: I75d518900a7cf17f51b0d466bc2d062c470790bb