use local setup value

Hi,

In except *node_js* or *perl*, it does not execute.
I wanted to fix this by #4.

```
$ test-travis
# running .travis.yml
Use of uninitialized value in subroutine entry at /Users/hattori-h/.cpanm/lib/perl5/App/test/travis.pm line 167.
Can't use string ("") as a subroutine ref while "strict refs" in use at /Users/hattori-h/.cpanm/lib/perl5/App/test/travis.pm line 167.
```

Thanks.