Summary:
We sometimes get reports about corrupted repos. Usually the corrupted part
is just at the end of changelog or manifest.
Truncating them manually works but people need to be very careful. This
extension is like the manual fix but automatized.
Test Plan:
Run `hg debugfixcorrupt --no-dryrun` on a reported corrupted repo and check
it truncates files correctly and the repo passes `hg verify` afterwards.
Reviewers: #mercurial, durham, stash
Reviewed By: stash
Subscribers: stash, rmcelroy, durham, lcharignon, mjpieters
Differential Revision: https://phabricator.intern.facebook.com/D3408396
Signature: t1:3408396:1491897232:fc17a105124b568963441adfec97e26735df3258
