Avoid generating source maps for packages with no files.
Avoid generating source maps for packages with no files.

Chrome has difficulty parsing these (arguably useless) source maps,
anyway. I don't want to speak too soon, but this also seems to help with

mjmasn/meteor,jdivy/meteor,Hansoft/meteor,AnthonyAstige/meteor,jdivy/meteor,jdivy/meteor,mjmasn/meteor,4commerce-technologies-AG/meteor,jdivy/meteor,DAB0mB/meteor,DAB0mB/meteor,lorensr/meteor,Hansoft/meteor,nuvipannu/meteor,Hansoft/meteor,4commerce-technologies-AG/meteor,mjmasn/meteor,AnthonyAstige/meteor,chasertech/meteor,chasertech/meteor,nuvipannu/meteor,DAB0mB/meteor,AnthonyAstige/meteor,Hansoft/meteor,Hansoft/meteor,lorensr/meteor,nuvipannu/meteor,AnthonyAstige/meteor,DAB0mB/meteor,jdivy/meteor,nuvipannu/meteor,DAB0mB/meteor,chasertech/meteor,lorensr/meteor,AnthonyAstige/meteor,lorensr/meteor,lorensr/meteor,nuvipannu/meteor,mjmasn/meteor,Hansoft/meteor,mjmasn/meteor,4commerce-technologies-AG/meteor,nuvipannu/meteor,4commerce-technologies-AG/meteor,jdivy/meteor,AnthonyAstige/meteor,chasertech/meteor,4commerce-technologies-AG/meteor,mjmasn/meteor,4commerce-technologies-AG/meteor,4commerce-technologies-AG/meteor,nuvipannu/meteor,DAB0mB/meteor,AnthonyAstige/meteor,lorensr/meteor,chasertech/meteor,chasertech/meteor,DAB0mB/meteor,Hansoft/meteor,AnthonyAstige/meteor,lorensr/meteor,chasertech/meteor,mjmasn/meteor,jdivy/meteor