fix error when trying to resolve changed file twice

plugins/c9.ide.watcher/gui.js

@@ -331,9 +331,11 @@ define(function(require, exports, module) {
         }
         
         function updateChangedPath(err, path, data) {
+            if (!changedPaths[path])
+                return;
             var tab = changedPaths[path].tab || tabManager.findTab(path);
             if (!tab)
-                return changedPaths[path] && changedPaths[path].resolve();
+                return changedPaths[path].resolve();
             var doc = tab.document;
             doc.setBookmarkedValue(data, true);
             doc.meta.timestamp = Date.now() - settings.timeOffset;