resolved-dnstls: remove deprecated openssl functions

There are replacements available in OpenSLL 1.1.0,
but those should not be needed. To quote the docs:

> As of version 1.1.0 OpenSSL will automatically allocate all resources
> that it needs so no explicit initialisation is required.
> Similarly it will also automatically deinitialise as required.

src/resolve/resolved-dnstls-openssl.c

@@ -392,9 +392,6 @@ int dnstls_manager_init(Manager *manager) {
 
         assert(manager);
 
-        ERR_load_crypto_strings();
-        SSL_load_error_strings();
-
         manager->dnstls_data.ctx = SSL_CTX_new(TLS_client_method());
         if (!manager->dnstls_data.ctx)
                 return -ENOMEM;