[geary/geary-0.11] Really fix (?) critical warning when changing conversations rapidly.

[Michael Gratton <mjog src gnome org>]

commit f690a279180fe24a99d430f11cb6fc2fcc5cd1ad
Author: Michael James Gratton <mike vee net>
Date:   Tue Aug 2 22:32:50 2016 +1000

    Really fix (?) critical warning when changing conversations rapidly.
    
    Commit f6518b0 relied on the load being cancelled, which only happens if
    you change conversation, not folder. Changing the foldler will eventually
    change the conversation, but not after a nnumber of async calls.
    
    Bug 714509.
    
    * src/client/conversation-viewer/conversation-viewer.vala
      (ConversationViewer::on_folder_selected): Cancel existing load before
      preceeding.

 .../conversation-viewer/conversation-viewer.vala   |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/client/conversation-viewer/conversation-viewer.vala 
b/src/client/conversation-viewer/conversation-viewer.vala
index 3579be7..7875bd9 100644
--- a/src/client/conversation-viewer/conversation-viewer.vala
+++ b/src/client/conversation-viewer/conversation-viewer.vala
@@ -419,6 +419,7 @@ public class ConversationViewer : Gtk.Box {
     
     private void on_folder_selected(Geary.Folder? folder) {
         hide_special_message();
+        cancel_load();
         
         current_folder = folder;
         email_store = (current_folder == null ? null : new Geary.App.EmailStore(current_folder.account));