add support for logind

I'm forwarding this commit by Rex Dieter to add logind support.

http://pkgs.fedoraproject.org/cgit/cinnamon-control-center.git/tree/cinnamon-control-center-login1.patch
add support for logind 

I'm forwarding this commit by Rex Dieter to add logind support.
Merge pull request #35 from leigh123linux/patch-7

 add support for logind