pgsql: More cleanup on roles patch.

Log Message:
-----------
More cleanup on roles patch.  Allow admin option to be inherited through
role memberships; make superuser/createrole distinction do something
useful; fix some locking and CommandCounterIncrement issues; prevent
creation of loops in the membership graph.

Modified Files:
--------------
    pgsql/src/backend/commands:
        dbcommands.c (r1.162 -> r1.163)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/dbcommands.c.diff?r1=1.162&r2=1.163)
        user.c (r1.154 -> r1.155)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/user.c.diff?r1=1.154&r2=1.155)
    pgsql/src/backend/parser:
        gram.y (r2.500 -> r2.501)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/gram.y.diff?r1=2.500&r2=2.501)
        keywords.c (r1.161 -> r1.162)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/keywords.c.diff?r1=1.161&r2=1.162)
    pgsql/src/backend/utils/adt:
        acl.c (r1.116 -> r1.117)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/acl.c.diff?r1=1.116&r2=1.117)
    pgsql/src/backend/utils/init:
        flatfiles.c (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/init/flatfiles.c.diff?r1=1.10&r2=1.11)
    pgsql/src/include/utils:
        acl.h (r1.79 -> r1.80)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/acl.h.diff?r1=1.79&r2=1.80)