Using of junk value in slab allocator similar to modern FreeBSD values.

src/core/ngx_slab.c

diff --git a/src/core/ngx_slab.c b/src/core/ngx_slab.c
index 9b5b28f..c7b6876 100644
--- a/src/core/ngx_slab.c
+++ b/src/core/ngx_slab.c
@@ -42,14 +42,14 @@
 
 #if (NGX_DEBUG_MALLOC)
 
-#define ngx_slab_junk(p, size)     ngx_memset(p, 0xD0, size)
+#define ngx_slab_junk(p, size)     ngx_memset(p, 0xA5, size)
 
 #else
 
 #if (NGX_HAVE_DEBUG_MALLOC)
 
 #define ngx_slab_junk(p, size)                                                \
-    if (ngx_debug_malloc)          ngx_memset(p, 0xD0, size)
+    if (ngx_debug_malloc)          ngx_memset(p, 0xA5, size)
 
 #else