fix Ubuntu bug

[andreabellitto]

fix ubuntu bug releated to "Bumblebee Failed to load module “mouse” (module does not exist, 0)"

[Lekensteyn]

See also #839

[andreabellitto]

#749 (comment)

It's releated to the fact that in newer Ubuntu versions the package xserver-xorg-input-mouse was removed and it's now replaced by the package xserver-xorg-input-all.

I had these error:
$ optirun glxspheres [ERROR]Cannot access secondary GPU - error: [XORG] (EE) Failed to load module "mouse" (module does not exist, 0)

and my commit solved the problem, for me, and for other people too.