stats: fix memory leak in stat_segment_dump_r()

The built stat_segment_data_t is leaked if stat_segment_access_end()
returns false.

Type: fix
Signed-off-by: Duncan Eastoe <duncan@graphiant.com>
Change-Id: I70adabbe7947d3e8a798cdfb3eaa14c683dce9da

src/vpp-api/client/stat_client.c

@@ -433,6 +433,8 @@ stat_segment_dump_r (uint32_t * stats, stat_client_main_t * sm)
 
   fprintf (stderr, "Epoch changed while reading, invalid results\n");
   // TODO increase counter
+  if (res)
+    stat_segment_data_free (res);
   return 0;
 }