key-exchange: Joint ke_test_vector format for DH and KEM

Both Diffie-Hellman (DH) and Key Encapsulation Mechanism (KEM) based
key exchange methods use a common ke_test_vector format. The
set_seed() function is used to provide deterministic private key
material for the crypto tests.

src/libstrongswan/plugins/gmp/gmp_diffie_hellman.c

@@ -135,8 +135,8 @@ METHOD(key_exchange_t, get_public_key, bool,
 	return TRUE;
 }
 
-METHOD(key_exchange_t, set_private_key, bool,
-	private_gmp_diffie_hellman_t *this, chunk_t value)
+METHOD(key_exchange_t, set_seed, bool,
+	private_gmp_diffie_hellman_t *this, chunk_t value, drbg_t *drbg)
 {
 	mpz_import(this->xa, value.len, 1, 1, 1, 0, value.ptr);
 	mpz_powm(this->ya, this->g, this->xa, this->p);
@@ -228,7 +228,7 @@ static gmp_diffie_hellman_t *create_generic(key_exchange_method_t group,
 				.get_shared_secret = _get_shared_secret,
 				.set_public_key = _set_public_key,
 				.get_public_key = _get_public_key,
-				.set_private_key = _set_private_key,
+				.set_seed = _set_seed,
 				.get_method = _get_method,
 				.destroy = _destroy,
 			},