pgsql: Add a failure check for syslogger's use of _beginthreadex(), and

Log Message:
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Add a failure check for syslogger's use of _beginthreadex(), and remove
unnecessary thread address output parameter, to make this code look more
like that in pg_restore.

Modified Files:
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pgsql/src/backend/postmaster:
syslogger.c (r1.47 -> r1.48)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/syslogger.c?r1=1.47&r2=1.48)