pgbouncer - pgbouncer: Make crypt authentication optional.

Log Message:
-----------
Make crypt authentication optional.

It was removed from PostgreSQL 8.4 sources.

Modified Files:
--------------
pgbouncer:
configure.ac (r1.48 -> r1.49)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/configure.ac.diff?r1=1.48&r2=1.49)
pgbouncer/include:
system.h (r1.16 -> r1.17)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/include/system.h.diff?r1=1.16&r2=1.17)
pgbouncer/src:
client.c (r1.24 -> r1.25)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/client.c.diff?r1=1.24&r2=1.25)
main.c (r1.51 -> r1.52)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/main.c.diff?r1=1.51&r2=1.52)
proto.c (r1.16 -> r1.17)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgbouncer/pgbouncer/src/proto.c.diff?r1=1.16&r2=1.17)