vcl: fix coverity warning

Type:fix

Change-Id: I7b91ce9359f94131882ab430606586b1a6cf3e02
Signed-off-by: Florin Coras <fcoras@cisco.com>
diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index 69d9285..d449fb9 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -1570,7 +1570,8 @@
 
   session->listener_index = parent_session_index;
   parent_session = vcl_session_get_w_handle (wrk, parent_session_handle);
-  parent_session->n_accepted_sessions++;
+  if (parent_session)
+    parent_session->n_accepted_sessions++;
 
   session = vcl_session_get (wrk, session_index);
   VDBG (0, "session %u [0x%llx]: connect %s!", session->session_index,