pgbouncer - pgbouncer: minor cleanups - avoid use of non-const fmt

Log Message:
-----------
minor cleanups

- avoid use of non-const fmt string
- avoid duplicate def of sbuf_len

Modified Files:
--------------
pgbouncer/include:
bouncer.h (r1.22 -> r1.23)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/bouncer.h.diff?r1=1.22&r2=1.23)
iobuf.h (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/iobuf.h.diff?r1=1.4&r2=1.5)
pgbouncer/src:
main.c (r1.58 -> r1.59)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/main.c.diff?r1=1.58&r2=1.59)