Duplicate files with Gem dependency using `:path`

I've been using warbler to build a gem where one of the dependencies are :path => to a local gem 
```
gem "some-gem", :path => "./gems/some-gem"
```

I've noticed that warbler is including the built gem in a gem directory within the JAR & the source directory itself (`./gems/some-gem`) from the :path variable

Not a big deal but it causes 2x files to be included for size/bloat