Correct "agument" to "argument", not "augment"

See: <https://github.com/facebook/arcanist/pull/162>

It looks like the word `argument` appears many more times than `augment`, so I'm assuming `agument` is most likely to be a typo of `argument`.

Reviewed by: epriestley
Add "CURLFile" to the class whitelist

Summary: See D8876, etc.

Test Plan: ~o.O~

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D8877
It should be also valid to have empty change under hg

Summary: Like git, it is also valid to have empty net change under hg. Should not throw if that is the case.

Test Plan: Tried on a hg repo.

Reviewers: lifeihuang, #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D8888
Merge branch 'master' of github.com:facebook/arcanist