relay plugin ignores empty $ENV{RELAYCLIENT}

[frank]

Upgrading from a heavily customized and ancient version, I've always used 
an empty $RELAYCLIENT in my tcpserver configs but the latest version 
ignores the empty variable. This fixed it for me.

-frank


diff --git a/plugins/relay b/plugins/relay
index fdae3ad..6c7974b 100644
--- a/plugins/relay
+++ b/plugins/relay
@@ -230,7 +230,7 @@ sub hook_connect {
         return DECLINED;
     }

-    if ($ENV{RELAYCLIENT}) {
+    if (defined $ENV{RELAYCLIENT}) {
         $self->qp->connection->relay_client(1);
         $self->log(LOGINFO, "pass, enabled by env");
         return DECLINED;