Fix race condidtion in walking code
Fix race condidtion in walking code

When the walk function is called, and it is already waiting for the
previous walk task to finish, it simply exits.  This only happens when
called repeativly very quickly.

merlinblack/Game-Engine-Testbed,merlinblack/Game-Engine-Testbed,merlinblack/Game-Engine-Testbed,merlinblack/Game-Engine-Testbed