Addons: Fix installing official addons through drag & drop

Installing official addons through drag & drop doesn work from cleaning the addons names onwards. The mismatch occurs when we compare cleaned addon name with the zip file name. Since the officical addon name was cleaned it doesn't match the uncleaned zip filename.

Orange/canvas/application/addons.py

@@ -588,7 +588,7 @@ def dropEvent(self, event):
             if path.endswith(self.ADDON_EXTENSIONS):
                 name, vers, summary, descr = (get_meta_from_archive(path) or
                                               (os.path.basename(path), '', '', ''))
-                names.append(name)
+                names.append(cleanup(name))
                 packages.append(
                     Installable(name, vers, summary,
                                 descr or summary, path, [path]))