Search builder export crashed when using not null operator

SQL error due to enum definition not including the IS NULL & IS NOT NULL operators

[debug_info] => INSERT INTO civicrm_mapping_field (mapping_id , name , contact_type , column_number , grouping , operator , value ) VALUES ( 544 , 'membership_status' , 'Membership' , 0 , 1 , 'IS NOT NULL' , '' ) [nativecode=1265 ** Data truncated for column 'operator' at row 1]
[type] => DB_Error

Note the commit for this can be merged into 4.5 without doing any damage as it is in the 4.4.7 upgrade file & later changes to the operator field (converting it to a 16 char varchar will still take place