Update setup.bridge.sh

Replace "sudo -A su -c" with "sudo -A bash -c" to eliminate last two "X11 connection rejected..." messagages.
Update setup.sh

Replace "sudo -A su -c" with "sudo -A bash -c" to eliminate last two "X11 connection rejected..." messages.
Merge pull request #338 from muggins/master

changing "sudo -A su -c" to sudo -A bash -c in setup.sh and setup.bridge.sh