CB-5751 FirefoxOS build issue
(untested, as I have no Windows. coppied from version.bat, so it shoud be a no-brainer)
Simplifies build for firefoxos
Merge branch 'CB-5751' of https://github.com/Steckelfisch/cordova-firefoxos
Merge branch 'fix-build' of https://github.com/mozilla-cordova/cordova-firefoxos