Revert "Fix for x-caja-desktop windows at login"

This reverts commit d116bf8ba8be698869fef81b30d576bcacf3234c.

Revert because it does not solve the problem and it causes problems
for users with other docks like plank. See issue #211.
Merge pull request #215 from infirit/1.6

Revert "Fix for x-caja-desktop windows at login"