pgsql: Clean up a few places where Datums were being treated as pointers

Log Message:
-----------
Clean up a few places where Datums were being treated as pointers (and vice
versa) without going through DatumGetPointer.

Gavin Sherry, with Feng Tian.

Modified Files:
--------------
    pgsql/src/backend/access/common:
        heaptuple.c (r1.120 -> r1.121)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/common/heaptuple.c?r1=1.120&r2=1.121)
        indextuple.c (r1.85 -> r1.86)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/common/indextuple.c?r1=1.85&r2=1.86)
        printtup.c (r1.101 -> r1.102)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/common/printtup.c?r1=1.101&r2=1.102)
        reloptions.c (r1.9 -> r1.10)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/common/reloptions.c?r1=1.9&r2=1.10)
    pgsql/src/backend/access/heap:
        tuptoaster.c (r1.86 -> r1.87)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/heap/tuptoaster.c?r1=1.86&r2=1.87)
    pgsql/src/backend/utils/fmgr:
        fmgr.c (r1.114 -> r1.115)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/fmgr/fmgr.c?r1=1.114&r2=1.115)
    pgsql/src/pl/plpgsql/src:
        pl_exec.c (r1.209 -> r1.210)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_exec.c?r1=1.209&r2=1.210)