testing: Added drbg plugin where required

testing/hosts/winnetou/etc/strongswan.conf

@@ -1,5 +1,5 @@
 # strongswan.conf - strongSwan configuration file
 
 pki {
-  load = random pem sha1 sha2 sha3 pkcs1 pkcs8 pem gmp mgf1 bliss curve25519 x509 openssl
+  load = random drbg pem sha1 sha2 sha3 pkcs1 pkcs8 pem gmp mgf1 bliss curve25519 x509 openssl
 }