libdpkg: Use %zu instead of %d in varbuf_grow's internerr call

lib/dpkg/varbuf.c

@@ -119,7 +119,7 @@ varbuf_grow(struct varbuf *v, size_t need_size)
 {
   /* Make sure the varbuf is in a sane state. */
   if (v->size < v->used)
-    internerr("inconsistent varbuf: size(%d) < used(%d)", v->size, v->used);
+    internerr("inconsistent varbuf: size(%zu) < used(%zu)", v->size, v->used);
 
   /* Check if we already have enough room. */
   if ((v->size - v->used) >= need_size)