BUG #7561: syslogger doesn't close stdout and stderr

The following bug has been logged on the website:

Bug reference:      7561
Logged by:          Reinhard Max
Email address:      max@suse.de
PostgreSQL version: 9.1.5
Operating system:   openSUSE
Description:        

When initially starting up, syslogger keeps stdout and stderr open instead
of closing them and reopening them from /dev/null for proper daemonisation.
This causes the process that triggers PostgreSQL to hang if it uses a pipe
to synchronize itself with the backgrounding of the server.

I've sent a proposed fix to Peter Eisentraut.