Typically the CallerInfo is looked up based on a phone number, in which case the '_id' column
contains the contact id.
However when the lookup is based on a phone row, the '_id' column is the row number we queried.
The contact id is stored somewhere else in a 'contact_id' column.
The current fix, checks the mime type of the contactRef URL to find out which column contains
the contact id.
I think the contact DB should be more consistent and always return the contact id AS contact_id even
in the phone number scenario.
Bug:2269240