ACL_CONNECT patch 6

I have changed the revoke part of the patch. This time no restrictions,
only a warning message about a possible lockout.

http://www.xs4all.nl/~gevik/patch/patch-0.6.diff

Tom, Alvaro,

Do you think this will be accepted?

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[gevik@voyager ~]$ createdb
CREATE DATABASE
[gevik@voyager ~]$ psql
Welcome to psql 8.2devel, the PostgreSQL interactive terminal.

Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit

gevik=# select datname,datacl from pg_catalog.pg_database;
datname | datacl
-----------+----------------------------
postgres |
gevik |
template1 | {=c/gevik,gevik=CTc/gevik}
template0 | {=c/gevik,gevik=CTc/gevik}
(4 rows)

gevik=# revoke connection on database gevik from public;
REVOKE
gevik=# revoke connection on database gevik from gevik;
WARNING: This revoke statement removes the last database connection
privilege from database gevik.
DETAIL: Unless you have superuser privileges you could be locked out
from connecting to this database.
REVOKE
gevik=# select datname,datacl from pg_catalog.pg_database;
datname | datacl
-----------+----------------------------
postgres |
template1 | {=c/gevik,gevik=CTc/gevik}
template0 | {=c/gevik,gevik=CTc/gevik}
gevik | {=T/gevik,gevik=CT/gevik}