CRM-4732 Fields for select box export as labels instead of values

In a contact custom data field, if a select box is used the fields are placed into the database correctly but exported incorrectly.

For instance in a custom 'How did you hear about us" field, the labeled was "Host A" assigned an internal campaign code as "XXX" that was placed as the value.

The database field is recorded as "XXX" in MySql, but upon export, the field's label is exported and reads "Host A" in the CSV rather than "XXX".