server: immediately return to caller when processing sendToPeer

This commit alters the logic of processing sendToPeer requests within
the server to immediately return to the caller after locating the
target peer.

server.go

@@ -640,11 +640,11 @@ out:
 				}
 				s.peersMtx.RUnlock()
 
+				sMsg.errChan <- nil
+
 				for _, msg := range sMsg.msgs {
 					targetPeer.queueMsg(msg, nil)
 				}
-
-				sMsg.errChan <- nil
 			}()
 		case query := <-s.queries:
 			switch msg := query.(type) {