block-verify: fix 32-bit build

Reported-by: NPeter Lemenkov <lemenkov@gmail.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

block/blkverify.c

@@ -58,7 +58,7 @@ static void blkverify_err(BlkverifyAIOCB *acb, const char *fmt, ...)
     va_list ap;
 
     va_start(ap, fmt);
-    fprintf(stderr, "blkverify: %s sector_num=%ld nb_sectors=%d ",
+    fprintf(stderr, "blkverify: %s sector_num=%" PRId64 " nb_sectors=%d ",
             acb->is_write ? "write" : "read", acb->sector_num,
             acb->nb_sectors);
     vfprintf(stderr, fmt, ap);