pgsql: Make the behavior of HAVING without GROUP BY conform to the SQL

Log Message:
-----------
Make the behavior of HAVING without GROUP BY conform to the SQL spec.
Formerly, if such a clause contained no aggregate functions we mistakenly
treated it as equivalent to WHERE.  Per spec it must cause the query to
be treated as a grouped query of a single group, the same as appearance
of aggregate functions would do.  Also, the HAVING filter must execute
after aggregate function computation even if it itself contains no
aggregate functions.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        query.sgml (r1.43 -> r1.44)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/query.sgml.diff?r1=1.43&r2=1.44)
    pgsql/doc/src/sgml/ref:
        select.sgml (r1.81 -> r1.82)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/select.sgml.diff?r1=1.81&r2=1.82)
    pgsql/src/backend/executor:
        nodeGroup.c (r1.59 -> r1.60)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/nodeGroup.c.diff?r1=1.59&r2=1.60)
    pgsql/src/backend/nodes:
        copyfuncs.c (r1.296 -> r1.297)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/copyfuncs.c.diff?r1=1.296&r2=1.297)
        equalfuncs.c (r1.235 -> r1.236)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/equalfuncs.c.diff?r1=1.235&r2=1.236)
    pgsql/src/backend/optimizer/path:
        allpaths.c (r1.123 -> r1.124)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/path/allpaths.c.diff?r1=1.123&r2=1.124)
    pgsql/src/backend/optimizer/plan:
        createplan.c (r1.175 -> r1.176)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/plan/createplan.c.diff?r1=1.175&r2=1.176)
        planner.c (r1.178 -> r1.179)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/plan/planner.c.diff?r1=1.178&r2=1.179)
    pgsql/src/backend/optimizer/util:
        pathnode.c (r1.111 -> r1.112)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/util/pathnode.c.diff?r1=1.111&r2=1.112)
    pgsql/src/backend/parser:
        analyze.c (r1.315 -> r1.316)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/analyze.c.diff?r1=1.315&r2=1.316)
        parse_agg.c (r1.66 -> r1.67)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_agg.c.diff?r1=1.66&r2=1.67)
    pgsql/src/backend/rewrite:
        rewriteHandler.c (r1.147 -> r1.148)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/rewrite/rewriteHandler.c.diff?r1=1.147&r2=1.148)
        rewriteManip.c (r1.89 -> r1.90)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/rewrite/rewriteManip.c.diff?r1=1.89&r2=1.90)
    pgsql/src/include/nodes:
        parsenodes.h (r1.272 -> r1.273)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/parsenodes.h.diff?r1=1.272&r2=1.273)
    pgsql/src/include/optimizer:
        planmain.h (r1.79 -> r1.80)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/optimizer/planmain.h.diff?r1=1.79&r2=1.80)
    pgsql/src/include/rewrite:
        rewriteManip.h (r1.39 -> r1.40)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/rewrite/rewriteManip.h.diff?r1=1.39&r2=1.40)
    pgsql/src/test/regress/expected:
        select_having.out (r1.9 -> r1.10)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/select_having.out.diff?r1=1.9&r2=1.10)
        select_having_1.out (r1.3 -> r1.4)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/select_having_1.out.diff?r1=1.3&r2=1.4)
        select_having_2.out (r1.1 -> r1.2)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/select_having_2.out.diff?r1=1.1&r2=1.2)
    pgsql/src/test/regress/sql:
        select_having.sql (r1.8 -> r1.9)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/select_having.sql.diff?r1=1.8&r2=1.9)