Environment canonicalization bugs

[JeremieMelo]

line 1346
for key, val in env:
I don't think this works, because you cannot iterate dict like this, you have to write like this ：
for key, val in env.items() rights?

(Edit by @effigies):
From #2327:

line 1350:
val = key.encode('utf-8')
???? I think it should be:
val = val.encode('utf-8')

[effigies]

Thanks for the reports. Collapsing into a single report with a descriptive title.