vlib: don't leak node frames on refork

Free node frames in worker mains on refork. Otherwise these frames are
never returned to free pool and it causes massive memory leaks if
performed under traffic load

Type: fix
Signed-off-by: Dmitry Valter <d-valter@yandex-team.ru>
Change-Id: I15cbf024a3f4b4082445fd5e5aaa10bfcf77f363

src/vlib/node.h

@@ -389,6 +389,9 @@ typedef struct vlib_frame_t
   /* Number of vector elements currently in frame. */
   u16 n_vectors;
 
+  /* Index of frame size corresponding to allocated node. */
+  u16 frame_size_index;
+
   /* Scalar and vector arguments to next node. */
   u8 arguments[0];
 } vlib_frame_t;