Fixed fall-through behavior in method definition.
Fixed fall-through behavior in method definition.

My previous commit fixed a bug in how the method handles the `filename` argument, but introduced a new one in that I hadn't updated the method's default `filename` value to _also_ be a hash. This commit fixes that.
gynter/jekyll-import,danbernier/jekyll-import,danbernier/jekyll-import,stefanw/jekyll-import,cityoffortworth/jekyll-import,danbernier/jekyll-import,jekyll/jekyll-import,supriyantomaftuh/jekyll-import,Teino1978-Corp/jekyll-import,gynter/jekyll-import,stefanw/jekyll-import,ligthyear/jekyll-import,geerlingguy/jekyll-import,supriyantomaftuh/jekyll-import,shybovycha/jekyll-import,Teino1978-Corp/jekyll-import,jekyll/jekyll-import,ligthyear/jekyll-import,shybovycha/jekyll-import,geerlingguy/jekyll-import,Teino1978-Corp/jekyll-import,geerlingguy/jekyll-import,supriyantomaftuh/jekyll-import,cityoffortworth/jekyll-import,gynter/jekyll-import,shybovycha/jekyll-import,ligthyear/jekyll-import,stefanw/jekyll-import