util: restore the util.pickle symbol...
util: restore the util.pickle symbol
This was accidently dropped in df56e6bd37f6, which started importing pickle
directly. That commit explicitly says it will retain it for compatibility with
external stuff though.
The unused import in pycompat isn't flagged because that module is skipped.
Just importing with a comment seemed cleaner than `import X as Y` and then
assigning to a `pickle` variable, just to avoid the pyflakes warning.
Differential Revision:
https://phab.mercurial-scm.org/D12419
