[polari] chatView: Fix ScrollDirection typo in _onScroll

[Florian Müllner <fmuellner src gnome org>]

commit f928f7b7cac77cde1559856a8139574a35515adf
Author: Hashem Nasarat <hashem riseup net>
Date:   Thu Jan 14 23:20:27 2016 -0500

    chatView: Fix ScrollDirection typo in _onScroll
    
    This caused the following error to be logged when scrolling.
    
    JS ERROR: TypeError: Gtk.ScrollDirection is undefined
    
    https://bugzilla.gnome.org/show_bug.cgi?id=760653

 src/chatView.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/chatView.js b/src/chatView.js
index 6cbf99a..714eab6 100644
--- a/src/chatView.js
+++ b/src/chatView.js
@@ -539,7 +539,7 @@ const ChatView = new Lang.Class({
 
     _onScroll: function(w, event) {
         let [hasDir, dir] = event.get_scroll_direction();
-        if (hasDir && dir != Gtk.ScrollDirection.UP)
+        if (hasDir && dir != Gdk.ScrollDirection.UP)
             return Gdk.EVENT_PROPAGATE;
 
         let [hasDeltas, dx, dy] = event.get_scroll_deltas();