lfs: drop the unused progressbar code in the `filewithprogress` class...
lfs: drop the unused progressbar code in the `filewithprogress` class
This has been unused since f98fac24b757, which added worker based transfers for
concurrency, shifting the progressbar maintenance to the single thread waiting
on the worker to complete. Since the name no longer fits, rename the class.
Differential Revision:
https://phab.mercurial-scm.org/D7956