rst alloc: align on reporting cpos too

Since we align in rst_mem_alloc, we should also align when reporting the
current position; if we don't and things get unlucky, we report a different
position than where the pointer is actually allocated, which fucks things
up quite bad :)

Closes #111
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

rst-malloc.c

@@ -128,7 +128,7 @@ unsigned long rst_mem_cpos(int type)
 {
 	struct rst_mem_type_s *t = &rst_mems[type];
 	BUG_ON(!t->remapable || !t->enabled);
-	return t->free_mem - t->buf;
+	return ((void*) round_up((unsigned long)t->free_mem, sizeof(void *))) - t->buf;
 }
 
 void *rst_mem_remap_ptr(unsigned long pos, int type)