testing: Load kdf plugin in all scenarios that require it

Once we use plugin-provided prf+() these won't work otherwise.

testing/tests/ikev2-stroke/rw-eap-peap-mschapv2/hosts/carol/etc/strongswan.conf

@@ -1,6 +1,6 @@
 # /etc/strongswan.conf - strongSwan configuration file
 
 charon {
-  load = random nonce aes des sha1 sha2 md4 md5 pem pkcs1 curve25519 mfg1 gmp x509 curl revocation hmac stroke kernel-netlink socket-default eap-identity eap-mschapv2 eap-peap updown
+  load = random nonce aes des sha1 sha2 md4 md5 pem pkcs1 curve25519 mfg1 gmp x509 curl revocation hmac kdf stroke kernel-netlink socket-default eap-identity eap-mschapv2 eap-peap updown
   multiple_authentication=no
 }

testing/tests/ikev2-stroke/rw-eap-peap-mschapv2/hosts/dave/etc/strongswan.conf

@@ -1,6 +1,6 @@
 # /etc/strongswan.conf - strongSwan configuration file
 
 charon {
-  load = random nonce aes des sha1 sha2 md4 md5 pem pkcs1 curve25519 mfg1 gmp x509 curl revocation hmac stroke kernel-netlink socket-default eap-identity eap-mschapv2 eap-peap updown
+  load = random nonce aes des sha1 sha2 md4 md5 pem pkcs1 curve25519 mfg1 gmp x509 curl revocation hmac kdf stroke kernel-netlink socket-default eap-identity eap-mschapv2 eap-peap updown
   multiple_authentication=no
 }

testing/tests/ikev2-stroke/rw-eap-peap-mschapv2/hosts/moon/etc/strongswan.conf

@@ -1,7 +1,7 @@
 # /etc/strongswan.conf - strongSwan configuration file
 
 charon {
-  load = random nonce aes des sha1 sha2 md4 md5 pem pkcs1 curve25519 mfg1 gmp x509 curl revocation hmac stroke kernel-netlink socket-default eap-identity eap-mschapv2 eap-peap updown
+  load = random nonce aes des sha1 sha2 md4 md5 pem pkcs1 curve25519 mfg1 gmp x509 curl revocation hmac kdf stroke kernel-netlink socket-default eap-identity eap-mschapv2 eap-peap updown
   multiple_authentication=no
   plugins {
     eap-peap {