pgsql: Update SysV parameter configuration documentation for FreeBSD.

Update SysV parameter configuration documentation for FreeBSD.

FreeBSD hasn't made any use of kern.ipc.semmap since 1.1, and newer
releases reject attempts to set it altogether; so stop recommending
that it be adjusted.  Per bug #11161.

Back-patch to all supported branches.  Before 9.3, also incorporate
commit 7a42dff47, which touches the same text and for some reason
was not back-patched at the time.

Branch
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REL9_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/c5e2333aaf510dce45d8de7deb461d8569832839

Modified Files
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doc/src/sgml/runtime.sgml |   30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)