pgsql: Remove the recently added node types ReloptElem and OptionDefElem

Log Message:
-----------
Remove the recently added node types ReloptElem and OptionDefElem in favor
of adding optional namespace and action fields to DefElem.  Having three
node types that do essentially the same thing bloats the code and leads
to errors of confusion, such as in yesterday's bug report from Khee Chin.

Modified Files:
--------------
    pgsql/src/backend/access/common:
        reloptions.c (r1.25 -> r1.26)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/common/reloptions.c?r1=1.25&r2=1.26)
    pgsql/src/backend/commands:
        define.c (r1.103 -> r1.104)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/define.c?r1=1.103&r2=1.104)
        foreigncmds.c (r1.6 -> r1.7)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/foreigncmds.c?r1=1.6&r2=1.7)
        sequence.c (r1.158 -> r1.159)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/sequence.c?r1=1.158&r2=1.159)
        typecmds.c (r1.132 -> r1.133)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/typecmds.c?r1=1.132&r2=1.133)
        view.c (r1.114 -> r1.115)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/view.c?r1=1.114&r2=1.115)
    pgsql/src/backend/nodes:
        copyfuncs.c (r1.427 -> r1.428)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/copyfuncs.c?r1=1.427&r2=1.428)
        equalfuncs.c (r1.350 -> r1.351)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/equalfuncs.c?r1=1.350&r2=1.351)
        makefuncs.c (r1.63 -> r1.64)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/makefuncs.c?r1=1.63&r2=1.64)
        outfuncs.c (r1.356 -> r1.357)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/outfuncs.c?r1=1.356&r2=1.357)
    pgsql/src/backend/parser:
        gram.y (r2.660 -> r2.661)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/gram.y?r1=2.660&r2=2.661)
        parse_clause.c (r1.187 -> r1.188)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/parse_clause.c?r1=1.187&r2=1.188)
    pgsql/src/include/commands:
        defrem.h (r1.93 -> r1.94)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/commands/defrem.h?r1=1.93&r2=1.94)
    pgsql/src/include/foreign:
        foreign.h (r1.3 -> r1.4)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/foreign/foreign.h?r1=1.3&r2=1.4)
    pgsql/src/include/nodes:
        makefuncs.h (r1.66 -> r1.67)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/makefuncs.h?r1=1.66&r2=1.67)
        nodes.h (r1.221 -> r1.222)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/nodes.h?r1=1.221&r2=1.222)
        parsenodes.h (r1.392 -> r1.393)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/parsenodes.h?r1=1.392&r2=1.393)