Fix bug #727544 by telling elogind that we're a greeter
===================================================================
--- a/app.cpp
+++ b/app.cpp
@@ -290,6 +290,7 @@
 		pam.start("slim");
 		pam.set_item(PAM::Authenticator::TTY, DisplayName);
 		pam.set_item(PAM::Authenticator::Requestor, "root");
+		pam.setenv("XDG_SESSION_CLASS", "greeter");
 	}
 	catch(PAM::Exception& e){
 		logStream << APPNAME << ": " << e << endl;