use consistent style for for loop in unmap(), no functional change

src/lib/libc/stdlib/malloc.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: malloc.c,v 1.244 2018/01/30 17:46:41 otto Exp $	*/
+/*	$OpenBSD: malloc.c,v 1.245 2018/02/07 18:58:30 otto Exp $	*/
 /*
  * Copyright (c) 2008, 2010, 2011, 2016 Otto Moerbeek <otto@drijf.net>
  * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org>
@@ -662,8 +662,7 @@ unmap(struct dir_info *d, void *p, size_t sz, size_t clear, int junk)
 	mask = mopts.malloc_cache - 1;
 	if (psz > rsz) {
 		size_t tounmap = psz - rsz;
-		i = 0;
-		for (;;) {
+		for (i = 0; ; i++) {
 			r = &d->free_regions[(i + offset) & mask];
 			if (r->p != NULL) {
 				rsz = r->size << MALLOC_PAGESHIFT;
@@ -681,7 +680,6 @@ unmap(struct dir_info *d, void *p, size_t sz, size_t clear, int junk)
 					break;
 				}
 			}
-			i++;
 		}
 	}
 	for (i = 0; ; i++) {