url: ignore some future pytype error

As soon as we start using the builtins `hasattr` function, pytype will start
getting confused about which types are available or not. So we ignore this error
beforehand.

mercurial/url.py

@@ -541,7 +541,10 b' def opener('
     else:
         handlers.append(httphandler(timeout=timeout))
         if has_https:
-            handlers.append(httpshandler(ui, timeout=timeout))
+            # pytype get confused about the conditional existence for httpshandler here.
+            handlers.append(
+                httpshandler(ui, timeout=timeout)  # pytype: disable=name-error
+            )
 
     handlers.append(proxyhandler(ui))