Fixed column inconsistency for theme-based ringtones.

Theme ringtones returned by the RingtoneManager must use the title
column to guarantee column naming consistency with other ringtone
sources.  Without this it's possible that the RingtonePickerActivity
will crash when trying to read the 'title' label column.

Change-Id: I133fe7b0c14981d3c9c5422e0a70ed2ef7572a25