Moved the foreign key constraint from new table on creation

Added data population to the new table prior to the foreign key addition.
   This covers systems with existing import data that have not had the import upstream consumer table created.
Foreign key application is conditional to cover systems that had original create script executed.
Merge pull request #417 from candlepin/wottop/move-import-upstream-fk

Removed the foreign key constraint to the new table on creation