testing: Load kdf plugin in all scenarios that require it

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

testing/tests/gcrypt-ikev1/alg-serpent/hosts/carol/etc/strongswan.conf

@@ -5,6 +5,6 @@ swanctl {
 }
 
 charon-systemd {
-  load = nonce pem pkcs1 gcrypt hmac x509 revocation curl vici kernel-netlink socket-default
+  load = nonce pem pkcs1 gcrypt hmac kdf x509 revocation curl vici kernel-netlink socket-default
   send_vendor_id = yes
 }

testing/tests/gcrypt-ikev1/alg-serpent/hosts/moon/etc/strongswan.conf

@@ -5,6 +5,6 @@ swanctl {
 }
 
 charon-systemd {
-  load = nonce pem pkcs1 gcrypt hmac x509 revocation vici kernel-netlink socket-default
+  load = nonce pem pkcs1 gcrypt hmac kdf x509 revocation vici kernel-netlink socket-default
   send_vendor_id = yes
 }

testing/tests/gcrypt-ikev1/alg-twofish/hosts/carol/etc/strongswan.conf

@@ -5,6 +5,6 @@ swanctl {
 }
 
 charon-systemd {
-  load = nonce pem pkcs1 gcrypt hmac x509 revocation curl vici kernel-netlink socket-default
+  load = nonce pem pkcs1 gcrypt hmac kdf x509 revocation curl vici kernel-netlink socket-default
   send_vendor_id = yes
 }

testing/tests/gcrypt-ikev1/alg-twofish/hosts/moon/etc/strongswan.conf

@@ -5,6 +5,6 @@ swanctl {
 }
 
 charon-systemd {
-  load = nonce pem pkcs1 gcrypt hmac x509 revocation vici kernel-netlink socket-default
+  load = nonce pem pkcs1 gcrypt hmac kdf x509 revocation vici kernel-netlink socket-default
   send_vendor_id = yes
 }