import is not working in combination with mach.props

I tried to make my machfile more modular with import (see https://github.com/DomainDrivenArchitecture/dda-cloudspec/blob/master/Machfile_not_working_modulatization.edn) but on execution I get warnings 

```
WARNING: Use of undeclared Var cljs.user/build-dir
WARNING: Use of undeclared Var cljs.user/terraform-build-dir
```
Properties values are nil ...
