Update driver.rb
Update driver.rb

Fixing https://github.com/fgrehm/vagrant-lxc/issues/353 issue

Val/vagrant-lxc,fgrehm/vagrant-lxc,ccope/vagrant-lxc,danielhodder/vagrant-lxc,danielhodder/vagrant-lxc,necrose99/vagrant-lxc,mayflower/vagrant-lxc,ccope/vagrant-lxc,danielhodder/vagrant-lxc,Val/vagrant-lxc,necrose99/vagrant-lxc,kevinlowrie/vagrant-lxc,fgrehm/vagrant-lxc,kevinlowrie/vagrant-lxc,mayflower/vagrant-lxc,mayflower/vagrant-lxc,fgrehm/vagrant-lxc,Val/vagrant-lxc,necrose99/vagrant-lxc,kevinlowrie/vagrant-lxc,ccope/vagrant-lxc