testing: make curve25519 the default DH group

testing/tests/libipsec/net2net-null/hosts/sun/etc/strongswan.conf

@@ -1,6 +1,6 @@
 # /etc/strongswan.conf - strongSwan configuration file
 
 charon {
-  load = pem pkcs1 random nonce revocation openssl curl stroke kernel-libipsec kernel-netlink socket-default updown
+  load = random nonce pem pkcs1 revocation openssl curl stroke kernel-libipsec kernel-netlink socket-default updown
   multiple_authentication = no
 }