pgsql: Allow row comparisons to be used as indexscan qualifications.

Log Message:
-----------
Allow row comparisons to be used as indexscan qualifications.
This completes the project to upgrade our handling of row comparisons.

Modified Files:
--------------
    pgsql/src/backend/access/nbtree:
        nbtsearch.c (r1.101 -> r1.102)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/nbtree/nbtsearch.c.diff?r1=1.101&r2=1.102)
        nbtutils.c (r1.69 -> r1.70)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/nbtree/nbtutils.c.diff?r1=1.69&r2=1.70)
    pgsql/src/backend/executor:
        nodeBitmapIndexscan.c (r1.14 -> r1.15)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/nodeBitmapIndexscan.c.diff?r1=1.14&r2=1.15)
        nodeIndexscan.c (r1.109 -> r1.110)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/nodeIndexscan.c.diff?r1=1.109&r2=1.110)
    pgsql/src/backend/optimizer/path:
        indxpath.c (r1.196 -> r1.197)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/path/indxpath.c.diff?r1=1.196&r2=1.197)
    pgsql/src/backend/optimizer/plan:
        createplan.c (r1.205 -> r1.206)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/plan/createplan.c.diff?r1=1.205&r2=1.206)
    pgsql/src/backend/optimizer/util:
        clauses.c (r1.205 -> r1.206)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/util/clauses.c.diff?r1=1.205&r2=1.206)
    pgsql/src/backend/utils/adt:
        selfuncs.c (r1.196 -> r1.197)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/selfuncs.c.diff?r1=1.196&r2=1.197)
    pgsql/src/include/access:
        skey.h (r1.30 -> r1.31)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/access/skey.h.diff?r1=1.30&r2=1.31)
    pgsql/src/include/executor:
        nodeIndexscan.h (r1.25 -> r1.26)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/executor/nodeIndexscan.h.diff?r1=1.25&r2=1.26)
    pgsql/src/include/optimizer:
        clauses.h (r1.81 -> r1.82)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/optimizer/clauses.h.diff?r1=1.81&r2=1.82)