manifest: remove unused property _oldmanifest
The last use seems to have gone away in
7c7d845f8b64 (manifest: make
manifestlog use it's own cache, 2016-11-10).
sslutil: reference fingerprints config option properly (
issue5559)
The config option is "host:fingerprints" not "host.fingerprints".
This warning message is bad and misleads users.
py3: convert key to str to make kwargs.pop work in mq
The keys are passed here and there as unicodes and our transformer make things
bytes. Due to that, mq was not poped and this results in error on Py3.
Here we abuse r'' to make that str on Python 3.