Update mount.rb
Update mount.rb

On Chef 11.16.4, line #19 fails with this error:

    NoMethodError: undefined method `device_name' for Chef::Resource::Mount

Removing the `private` access modifier makes the method call succeed.

Ruby 2.1.3p242
Ubuntu 12.04
RallySoftware-cookbooks/backup-cookbook,RallySoftware-cookbooks/backup-cookbook