Don't attempt to set SO_PASSCRED if Listen fails

ipc/ipc.go

@@ -42,13 +42,13 @@ func NewServer(address string, factory MsgFactory, log *logging.Logger, handlers
 	}
 
 	listener, err := net.ListenUnix("unix", &net.UnixAddr{address, "unix"})
-	if err := setPassCred(listener); err != nil {
-		return nil, errors.New("Failed to set SO_PASSCRED on listening socket: " + err.Error())
-	}
 	if err != nil {
 		md.close()
 		return nil, err
 	}
+	if err := setPassCred(listener); err != nil {
+		return nil, errors.New("Failed to set SO_PASSCRED on listening socket: " + err.Error())
+	}
 	done := make(chan bool)
 	idGen := newIdGen(done)
 	return &MsgServer{