Updates: Only log generic errors when checking for updates

That's because we're unable to give proper feedback to users about what
to do to solve the error.

spyder/workers/updates.py

@@ -166,15 +166,6 @@ def start(self):
             error_msg = HTTP_ERROR_MSG.format(status_code=page.status_code)
             logger.debug(err, stack_info=True)
         except Exception as err:
-            error = traceback.format_exc()
-            formatted_error = error.replace('\n', '<br>').replace(' ', '&nbsp;')
-
-            error_msg = _(
-                'It was not possible to check for Spyder updates due to the '
-                'following error:'
-                '<br><br>'
-                '<tt>{}</tt>'
-            ).format(formatted_error)
             logger.debug(err, stack_info=True)
 
         self.error = error_msg