pgsql: Update information about configuring SysV IPC parameters on NetB

Update information about configuring SysV IPC parameters on NetBSD.

Per Emmanuel Kasper, sysctl works fine as of NetBSD 5.0.

Branch
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REL8_3_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/50be28d2accc99a0daf49ef7bd692e828964be03

Modified Files
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doc/src/sgml/runtime.sgml |   63 ++++++++++++++++++++++++++++++++-------------
1 files changed, 45 insertions(+), 18 deletions(-)