Hi exonerated, you are completely right, the correct file to edit is /etc/rc.local, it is already changed in the tutorial.
About the problem of connection, (and sorry for my English): There is a solution for that. The problem seems to happen when the controller is paired to the BT dongle in the Raspberry, disconnected, paired on another device, and then paired again to the Raspberry. I think it happens because Bluez has some kind of bug.
Anyway, to fix that you need to delete the controller pair data, you need python-gobject, so:
sudo apt-get install python-gobject
And then:
bluez-simple-agent hciX XX:XX:XX:XX:XX:XX remove
Where X in hciX is the number of your BT device, usually 0 (hci0), check it with:
hciconfig
And XX:XX:XX:XX:XX:XX is the DS4 MAC, that you can get with:
hcitool scan
Once you do the bluez-simple-agent command, you can try ds4drv again, it should connect:
pi@raspberrypi ~ $ ds4drv –led 000008
[info][controller 1] Created devices /dev/input/js0 (joystick) /dev/input/event0 (evdev)
[info][bluetooth] Scanning for devices
[info][bluetooth] Found device A4:15:66:4E:CA:53
[info][controller 1] Connected to Bluetooth Controller (A4:15:66:4E:CA:53)
[info][bluetooth] Scanning for devices
[info][controller 1] Battery: 75%
[warning][controller 1] Signal strength is low (48 reports/s)