Partner Contact Details: Changes to DB Schema (and a related program change) to overcome a 'nant recreateDatabase' problem with PostgreSQL on certain machines.
* The error message that PostgreSQL gave when 'nant recreateDatabase' was run on Wolfgangs' and Alans' PC's (but not on mine and not on Windows Jenkins!) was: "[psql] Load sql commands from file: C:\openpetraorg\trunk/setup/petra0300/createconstraints-PostgreSQL.sql
psql:C:/openpetraorg/trunk/setup/petra0300/createconstraints-PostgreSQL.sql:3168: ERROR:  there is no unique constraint matching given keys for referenced table "p_partner_attribute_type"
* The PK having two columns, but the p_partner_attribute Table having a PK that only referenced of of them (p_code_c) can apparently upset PostgreSQL, I found while googling...

The changes I made:
* The PK on p_partner_attribute_type now only has one column (p_code_c), previously it had two (p_attribute_category_c, p_code_c). 
* I have added a Unique Constraint to get the same effect that multiple combinations of p_attribute_category_c, p_code_c are not allowed.