pgsql: Work around a documentation toolchain problem by replacing the

Log Message:
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Work around a documentation toolchain problem by replacing the "AIX-fixlevels"
table with a <variablelist> carrying the same information.  Previously the
9.0 documentation was failing to build as a US-size PDF file.  It's quite
obscure what the real problem is or why this avoids it, but we need a hack
now so we can build docs for beta4.

In passing do a bit of editing in the AIX installation docs, in particular
remove a long-obsolete claim that the regression tests are likely to fail.

Modified Files:
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    pgsql/doc/src/sgml:
        installation.sgml (r1.349 -> r1.350)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/installation.sgml?r1=1.349&r2=1.350)