cache table updates fail in pgsql

int(1) is not a valid data type for a postgres database :)

attached patch changes the data type to 'smallint', which seems to have standard usage in the database updates for postgresql, and most closely matches the corresponding data type in mysql.

tested as working. incidentally, we should probably have some kind of a rule where somebody actually _tries_ the updates for both mysql and postgresql before we commit a db update patch to core. :)