ip: fixup memory leak in function ip4_full_reass_drop_all

Type: fix

The vector 'to_free' allocated on heap should be freed to avoid memory leak.

Signed-off-by: barryxie <barryxie@tencent.com>
Change-Id: I539498b50a7f3e346c83b869fb400868961c233f
diff --git a/src/vnet/ip/reass/ip4_full_reass.c b/src/vnet/ip/reass/ip4_full_reass.c
index ba3a358..ce7771f 100644
--- a/src/vnet/ip/reass/ip4_full_reass.c
+++ b/src/vnet/ip/reass/ip4_full_reass.c
@@ -464,6 +464,7 @@
     {
       vlib_buffer_free (vm, to_free, vec_len (to_free));
     }
+  vec_free (to_free);
 }
 
 always_inline void