This is a new issue that gets linted with flake8 3.5.0. Basically you should
never use a blank except: statement.

This will catch all exceptions, including KeyboardInterrupt and SystemExit
(which is likely not intended). If a catch all is needed, use
`except: Exception`.  If you *really* mean to also catch KeyboardInterrupt et
al, use `except: BaseException`.

Of course, being specific is often better than a catch all.

MozReview-Commit-ID: FKx80MLO4RN

--HG--
extra : rebase_source : 7c74a7d0d81f2c984b47aff3a0ee3448b791177b