trickery bulletproofing

Prevent the pardoning of trickery in wizard mode from attempting
to continue when there's no longer any current level.  Also prevent
the ZEROCOMP configuration from trying to read from file descriptor -1
in case there're any other places which still let that slip through.
And fix an oddity in the VMS port's error() routine which has gone
unnoticed for years.

src/do.c

@@ -1055,6 +1055,8 @@ boolean at_stairs, falling, portal;
 					(int) new_ledger, depth(&u.uz), errno);
 			pline("Probably someone removed it.");
 			done(TRICKED);
+			/* we'll reach here if running in wizard mode */
+			error("Cannot continue this game.");
 		}
 		minit();	/* ZEROCOMP */
 		getlev(fd, hackpid, new_ledger, FALSE);