Fixes for flake8 master

[asottile]

I'm prepping the 3.6.0 flake8 release, figured I'd try some larger codebases :)

[asottile]

@RonnyPfannschmidt this one is subtle, and a new python3 behaviour:

exc = 'hi'
try:
    raise AssertionError('hello')
except Exception as exc:
    pass
print(exc)

$ python2 t.py
hello

$ python3 t.py 
Traceback (most recent call last):
  File "t.py", line 6, in <module>
    print(exc)
NameError: name 'exc' is not defined

from the docs

[RonnyPfannschmidt]

fabulous work, thanks for digging

[blueyed]

So why was the assert e is not None below not causing a problem before? (since e should have been deleted)

[blueyed]

Ah, likely untested code - i.e. it returned instead of going there I assume.

[asottile]

Retry code that was never hit 🤷‍♂️