ACL: re-enable command execution of disabled users.

After all I changed idea again: enabled/disabled should have a more
clear meaning, and it only means: you can't authenticate with such user
with new connections, however old connections continue to work as
expected.

src/acl.c

@@ -1055,10 +1055,6 @@ int ACLCheckCommandPerm(client *c, int *keyidxptr) {
     /* If there is no associated user, the connection can run anything. */
     if (u == NULL) return ACL_OK;
 
-    /* If the user is disabled we don't allow the execution of any
-     * command. */
-    if (!(u->flags & USER_FLAG_ENABLED)) return ACL_DENIED_CMD;
-
     /* Check if the user can execute this command. */
     if (!(u->flags & USER_FLAG_ALLCOMMANDS) &&
         c->cmd->proc != authCommand)