MEDIUM: spoe: Add support of ACLS to enable or disable sending of SPOE messages

Now, it is possible to conditionnaly send a SPOE message by adding an ACL-based
condition on the "event" line, in a "spoe-message" section. Here is the example
coming for the SPOE documentation:

    spoe-message get-ip-reputation
        args ip=src
        event on-client-session if ! { src -f /etc/haproxy/whitelist.lst }

To avoid mixin with proxy's ACLs, each SPOE message has its private ACL list. It
possible to declare named ACLs in "spoe-message" section, using the same syntax
than for proxies. So we can rewrite the previous example to use a named ACL:

    spoe-message get-ip-reputation
        args ip=src
	acl ip-whitelisted src -f /etc/haproxy/whitelist.lst
        event on-client-session if ! ip-whitelisted

ACL-based conditions are executed in the context of the stream that handle the
client and the server connections.
diff --git a/include/types/spoe.h b/include/types/spoe.h
index edbb459..193c2f6 100644
--- a/include/types/spoe.h
+++ b/include/types/spoe.h
@@ -184,6 +184,8 @@
 	struct list        args;    /* Arguments added when the SPOE messages is sent */
 	struct list        list;    /* Used to chain SPOE messages */
 
+	struct list        acls;    /* ACL declared on this message */
+	struct acl_cond   *cond;    /* acl condition to meet */
 	enum spoe_event    event;   /* SPOE_EV_* */
 };