This simply adds new screenshot for graphical_desktop_clean. I'm not
sure why font changed again hence I didn't included cantarell version in filename,
because I couldn't find one. Bodhi says that abattis-cantarell-fonts package
has version 0.0.17, on Github, Cantarell has version 0.24...
See https://openqa.fedoraproject.org/tests/27661#step/_graphical_wait_login/11