pgsql: Remove TypeName struct's timezone flag, which has been write-only

Log Message:
-----------
Remove TypeName struct's timezone flag, which has been write-only storage
for a very long time --- in current usage it's entirely redundant with the
name field.

Modified Files:
--------------
    pgsql/src/backend/nodes:
        copyfuncs.c (r1.389 -> r1.390)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/copyfuncs.c?r1=1.389&r2=1.390)
        equalfuncs.c (r1.319 -> r1.320)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/equalfuncs.c?r1=1.319&r2=1.320)
        outfuncs.c (r1.323 -> r1.324)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/nodes/outfuncs.c?r1=1.323&r2=1.324)
    pgsql/src/backend/parser:
        gram.y (r2.609 -> r2.610)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/gram.y?r1=2.609&r2=2.610)
    pgsql/src/include/nodes:
        parsenodes.h (r1.360 -> r1.361)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/nodes/parsenodes.h?r1=1.360&r2=1.361)