In the near future, all the values which cannot be converted to
vCard property is expressed as "X-ANDROID-CUSTOM" property + MIME_TYPE.
Example (Nick name):
X-ANDROID-CUSTOM:vnd.android.cursor.item/nickname;Nicky;;;;;;;;;;;;;
All the data are stored ordered by its column name ("data1" - "data15").
Currently the code assumes the max num is 15.
Internal Issue number: 2079082
837cba33c5