Comment 7 for bug 1407119

I've found a workaround. You can modify the file ~/.xscreensaver . The variable
  splash: True
should be switched to
  splash: False

You can do it by hand with
  # nano ~/.xscreensaver

or by executing these two lines which will make a backup (~/.xscreensaver.old) of the original configuration file and filter it with sed to place the modified version in the place of the previous one:
# cp ~/.xscreensaver ~/.xscreensaver.old
# sed 's/splash:.*/splash: False/' ~/.xscreensaver.old > ~/.xscreensaver

Once you are satisfied with the results, you can remove the backup file with
# rm ~/.xscreensaver.old