P2P: Clear old P2PS provision data

Receiving a provision discovery request for an ASP service that
has auto accept set to false should result in a provision discovery
response with the status field set to "currently unavailable".
Having stale P2PS provision data, results in sending a response with
the status set to success because it is mistakenly referred to as the
follow-on provision discovery request.

Fix that by clearing stale P2PS provision data in the following cases:
 1. When provision discovery is complete
 2. When ASP services are flushed (in which case old ASP provisioning
    is no longer valid).

Signed-off-by: Avrahams Stern <avraham.stern@intel.com>

src/p2p/p2p.c

@@ -2822,6 +2822,7 @@ void p2p_service_flush_asp(struct p2p_data *p2p)
 	}
 
 	p2p->p2ps_adv_list = NULL;
+	p2ps_prov_free(p2p);
 	p2p_dbg(p2p, "All ASP advertisements flushed");
 }