Pass ipsec.conf xauth_identity option via stroke to charon configurations

src/stroke/stroke_msg.h

@@ -246,6 +246,7 @@ struct stroke_msg_t {
 			u_int32_t eap_vendor;
 			char *eap_identity;
 			char *aaa_identity;
+			char *xauth_identity;
 			int mode;
 			int mobike;
 			int force_encap;