do not sent certreq payloads when using self-signed certs

testing/tests/ikev2/default-keys/hosts/carol/etc/ipsec.conf

@@ -20,4 +20,5 @@ conn home
 	right=PH_IP_MOON
 	rightsubnet=10.1.0.0/16
 	rightcert=peerCert.der
+	rightsendcert=never
 	auto=add

testing/tests/ikev2/default-keys/hosts/moon/etc/ipsec.conf

@@ -20,4 +20,5 @@ conn carol
 	leftfirewall=yes
 	right=%any
 	rightcert=peerCert.der
+	rightsendcert=never
 	auto=add