MEDIUM: http/tcp: permit to resume http and tcp custom actions

Later, the processing of some actions needs to be interrupted and resumed
later. This patch permit to resume the actions. The actions that needs
to run with the resume mode are not yet avalaible. It will be soon with
Lua patches. So the code added by this patch is untestable for the moment.

The list of "tcp_exec_req_rules" cannot resme because is called by the
unresumable function "accept_session".
diff --git a/src/session.c b/src/session.c
index 2e3b83f..aee816c 100644
--- a/src/session.c
+++ b/src/session.c
@@ -108,6 +108,11 @@
 	s->logs.logwait = p->to_log;
 	s->logs.level = 0;
 
+	/* Initialise the current rule list pointer to NULL. We are sure that
+	 * any rulelist match the NULL pointer.
+	 */
+	s->current_rule_list = NULL;
+
 	memset(s->stkctr, 0, sizeof(s->stkctr));
 
 	s->listener = l;