Fix consecutive returns in fakes with return values

[johwech]

• [x] Your code builds clean without any errors or warnings
• [x] You are not breaking consistency
• [ ] You have added unit tests
• [x] All tests and other checks pass

Fixes same issue as #86, but also in the ruby generator script.

[AppVeyorBot]

:white_check_mark: Build fff 88-appveyor completed (commit https://github.com/meekrosoft/fff/commit/57a5e4b9d7 by @johwech)