bihash template: avoid memory leak upon rehash

Call the BV (value_free) when we have performed the rehash
and thus no longer need the memory that old value for the
bucket refers to.

Change-Id: Ibb82174fc8002aeb3e1a6c8d1f90293d73bc45d8
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>
diff --git a/src/vppinfra/bihash_template.c b/src/vppinfra/bihash_template.c
index 2571c47..752597e 100644
--- a/src/vppinfra/bihash_template.c
+++ b/src/vppinfra/bihash_template.c
@@ -627,6 +627,9 @@
   tmp_b.lock = 0;
   CLIB_MEMORY_BARRIER ();
   b->as_u64 = tmp_b.as_u64;
+  /* free the old bucket */
+  v = BV (clib_bihash_get_value) (h, h->saved_bucket.offset);
+  BV (value_free) (h, v, h->saved_bucket.log2_pages);
   BV (clib_bihash_alloc_unlock) (h);
   return (0);
 }