Bug fix #34418

Fix for 2.66a

Screencast could be started twice in a row, but it then also added two handlers
for drawing an overlay circle around mouse cursor. After ending the screencast,
this circle then kept being drawn.



git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54961 954f8c5b-7b00-dc11-b283-0030488c597c