DOne!
Here is what I done:
cd ~/RetroPie-Setup/scriptmodules/ports
mv kodi.sh kodi.sh_15.2
nano kodi.sh
copy the code from the github wiki page( https://github.com/RetroPie/RetroPie-Setup/wiki/KODI) and then press [crtl] + ‘x‘ and then ‘y’ to save the new file.
Load up the RetroPie script and find Kodi in the experimental menu and install as normal
