make scan_scaled set errno to EINVAL rather than ERANGE if it encounters

an invalid multiplier, like the man page says it should
"looks sensible" deraadt@, ok ian@

src/lib/libutil/fmt_scaled.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: fmt_scaled.c,v 1.10 2009/06/20 15:00:04 martynas Exp $	*/
+/*	$OpenBSD: fmt_scaled.c,v 1.11 2012/11/12 14:07:20 halex Exp $	*/
 
 /*
  * Copyright (c) 2001, 2002, 2003 Ian F. Darwin.  All rights reserved.
@@ -177,7 +177,9 @@ scan_scaled(char *scaled, long long *result)
 			return 0;
 		}
 	}
-	errno = ERANGE;
+
+	/* Invalid unit or character */
+	errno = EINVAL;
 	return -1;
 }