Fixes #1550/#1546. Name hashing change to fix the build

Fixes #1550.

Some tests are failing after merging #1546. See https://travis-ci.org/sbt/sbt/builds/33265884

- actions / join
- compiler-project / inc-ant-style

## what this changes

inc.Relations.empty now take the default parameter `IncOptions.nameHashingDefault` instead of `false`.

/review @gkossakowski