Fixes errors in maya -batch trying to create a callback for non-existent UI.
Fixes errors in maya -batch trying to create a callback for non-existent UI.

ruschelp/cortex-vfx,ruschelp/cortex-vfx,code-google-com/cortex-vfx,code-google-com/cortex-vfx,code-google-com/cortex-vfx,ruschelp/cortex-vfx,code-google-com/cortex-vfx