BUG #1643: dbf2pg broken + quick fix

The following bug has been logged online:

Bug reference:      1643
Logged by:          Boris van Schooten
Email address:      schooten@cs.utwente.nl
PostgreSQL version: 7.4.5, 8.0.2
Operating system:   FreeBSD
Description:        dbf2pg broken + quick fix
Details:

As several people on the mailing lists have already noted, dbf2pg is broken.
 It usually fails to enter the numeric values from the dbf file in the sql
tables.  If you enable verbose output (-vv) you see "Illegal numeric value
found" errors.

As it turns out, the integer checking code (contrib/dbase/dbf2pg.c, function
isinteger) is broken.  It appears the function reports 0 in case it finds a
space in the dbf rather than a digit.  I disabled it (always made it return
1).  Now, my dbf files import fine.