managesieve-login: Use default_vsz_limit instead of adding our own.

This change matches identical changes for Dovecot's imap-login and pop3-login.

src/managesieve-login/managesieve-login-settings.c

@@ -51,7 +51,7 @@ struct service_settings managesieve_login_settings_service_settings = {
 	.client_limit = 0,
 	.service_count = 1,
 	.idle_kill = 0,
-	.vsz_limit = 64*1024*1024,
+	.vsz_limit = (uoff_t)-1,
 
 	.unix_listeners = ARRAY_INIT,
 	.fifo_listeners = ARRAY_INIT,