opscode-cookbooks/nginx — pull request #153 by tomduckering (2013-09-20 11:46:24+00:00)
Title: Using empty string repo_source as legal indicator for no repo install...

I was unable to set repo_source to nil - doing so simply resulted in it using the default of "epel"

So I allowed it use an empty string to indicate that I don't want it to set up any repos.