pull-requests: don't report abort type of ajax requests as errors.

rhodecode/templates/pullrequests/pullrequest.mako

@@ -313,9 +313,12 b''
 
       loadRepoRefDiffPreview._currentRequest = $.get(url)
           .error(function(data, textStatus, errorThrown) {
+                if (textStatus !== 'abort') {
                 alert(
                 "Error while processing request.\nError code {0} ({1}).".format(
                         data.status, data.statusText));
+                }
+
           })
           .done(function(data) {
               loadRepoRefDiffPreview._currentRequest = null;