Remove hard-coded vars from docs config.
Remove hard-coded vars from docs config.

Change-Id: I05df7d4784aeca88c4e9c2d89b45a6e4b8fac383

garydonovan/google-maps-services-python,stephenmcd/google-maps-services-python,edwardsamuel/google-maps-services-python,ambrozic/google-maps-services-python,Prindle19/google-maps-services-python,codeAshu/google-maps-services-python,Scronker/google-maps-services-python,googlemaps/google-maps-services-python