[shotwell] Fix frozen upload dialog

[Jens Georg <jensgeorg src gnome org>]

commit 9b0a0491494e39513fc8247a290ccc5e2638e182
Author: Jens Georg <mail jensge org>
Date:   Fri Sep 7 15:57:28 2018 +0200

    Fix frozen upload dialog
    
    Or rather work-around. Dispatch pending events. Proper solution would be
    to port the REST things to use Soup async API
    
    Fixes #22

 plugins/common/RESTSupport.vala | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/plugins/common/RESTSupport.vala b/plugins/common/RESTSupport.vala
index d92c2648..482fd2cd 100644
--- a/plugins/common/RESTSupport.vala
+++ b/plugins/common/RESTSupport.vala
@@ -190,6 +190,9 @@ public class Transaction {
 
     private void on_wrote_body_data(Soup.Buffer written_data) {
         bytes_written += (int) written_data.length;
+        while (Gtk.events_pending()) {
+            Gtk.main_iteration();
+        }
         chunk_transmitted(bytes_written, (int) message.request_body.length);
     }