py3: use `except error as e` instead of `except error, e`
The latter throws SyntaxError on Python 3.
Differential Revision: https://phab.mercurial-scm.org/D3613
--- a/tests/test-parseindex.t Sat May 19 18:56:00 2018 +0530
+++ b/tests/test-parseindex.t Sat May 19 18:58:35 2018 +0530
@@ -184,7 +184,7 @@
> try:
> f()
> print('uncaught buffer overflow?')
- > except ValueError, inst:
+ > except ValueError as inst:
> print(inst)
> EOF