update script to reflect deprecated session_manager_setup.sh

as indicated by the commit message, session_manager_setup.sh is deprecated,
and everything should now be in /etc/chrome_dev.conf. The script has been
updated accordingly, as well as fixing a typo so that the clientid was
actually added.
Merge pull request #1 from Androidsftw/master

thx, update script to reflect deprecated session_manager_setup.sh