pgsql: Fix problem that sscanf(buf, "%d", &val) eats leading white

Log Message:
-----------
Fix problem that sscanf(buf, "%d", &val) eats leading white space, but
our to_* functions were not handling that.

Modified Files:
--------------
pgsql/src/backend/utils/adt:
formatting.c (r1.109 -> r1.110)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/formatting.c.diff?r1=1.109&r2=1.110)