Summary:
Checkheads is a legacy feature that is less useful in our setups, namely:
- In commit cloud / Mononoke's world, it's intentional to have many heads.
Pushing a new head is a normal operation that should not be forbidden.
- With remotenames, remotenames performs the check and checkheads is
redundant, as shown by the added test.
So let's add a config option to turn it off first. Later we can remove the
feature and update all the tests.
Reviewed By: ryanmce
Differential Revision: D8148016
fbshipit-source-id: 71684f20b9ca37902440eae331292679b0feb4c6
