also clear the local control port when resetting the WTP state

Without reseting the port, the new control socket will be
bound to the same port as the old one.

src/wtp/wtp_dfa.c

@@ -583,4 +583,6 @@ void wtp_reset_state(void)
 
 	memset(&g_wtp.dtls.localaddr, 0, sizeof(g_wtp.dtls.localaddr));
 	memset(&g_wtp.dtls.peeraddr, 0, sizeof(g_wtp.dtls.peeraddr));
+
+	CAPWAP_SET_NETWORK_PORT(&g_wtp.net.localaddr, 0);
 }