suppress leak-detective stderr output in ipsec pool

testing/tests/ikev2/ip-two-pools-db/hosts/moon/etc/strongswan.conf

@@ -8,3 +8,7 @@ charon {
   }
   load = curl aes des sha1 sha2 md5 gmp random x509 pubkey hmac xcbc stroke sqlite sql kernel-netlink updown
 }
+
+pool {
+  load = sqlite
+}