pipelimit: Fix memleak on shutdown

(cherry picked from commit ffdec6d38d0935d8af2633e3d3ded8a985ddfcca)

src/modules/pipelimit/pl_ht.c

@@ -102,6 +102,7 @@ int pl_init_htable(unsigned int hsize)
 
 void pl_pipe_free(pl_pipe_t *it)
 {
+	shm_free(it);
 	return;
 }