The dev/change-scala-version.sh [2.11] script modifies in-place the pom.xml files across all of the modules. This is a git-visible change. So if we wish to make changes to spark source in our own fork's - while developing with scala 2.11 - we would end up conflating those updates with our own.
A possible scenario would be to update .gitignore - by adding pom.xml. However I can not get that to work: .gitignore is tricky. Suggestions appreciated.
