MGASA-2015-0461 Updated lightdm packages fix security vulnerability

Updated lightdm corrects a possible denial of service attack CVE-2015-8316...

Fedora 20 : lightdm-1.7.15-1.fc20 (2013-16293)

New upstream bugfix release : - Correctly set permissions on Xauthority file. - Correctly set $XDGCURRENTDESKTOP for non-autologin sessions - Fix overallocation of array for strings from greeter. - Set XDGVTNR=1 as a fallback if using SeatUnity without a functioning compositor or working VT...