vlib: fix memory leak on process nodes reforking

The processes vector leaked on reforking and needs to be
freed before recloning from main node processes.

Type: fix
Signed-off-by: Vladislav Grishenko <themiron@yandex-team.ru>
Change-Id: Id69bc3fd42e2efacfcd521f98e6e51a9c712fef5
diff --git a/src/vlib/threads.c b/src/vlib/threads.c
index dade7bf..3cd8c01 100644
--- a/src/vlib/threads.c
+++ b/src/vlib/threads.c
@@ -1056,6 +1056,7 @@
 
   vec_free (old_rt);
 
+  vec_free (nm_clone->processes);
   nm_clone->processes = vec_dup_aligned (nm->processes,
 					 CLIB_CACHE_LINE_BYTES);
   nm_clone->node_by_error = nm->node_by_error;