pgsql: Tweak the order of processing of WITH clauses so that they are

Log Message:
-----------
Tweak the order of processing of WITH clauses so that they are processed
before we start analyzing the parent statement. This is to make it
more clear that the WITH isn't affected by anything in the parent.
I don't believe there's any actual bug here, because the stuff that
was being done before WITH didn't affect subqueries; but it's certainly
a potential for error (and apparently misled Marko into committing some
real errors...).

Modified Files:
--------------
pgsql/src/backend/parser:
analyze.c (r1.400 -> r1.401)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/analyze.c?r1=1.400&r2=1.401)