Blender Git Loki

OpenGL render: Bugfix (unreported) after rB6f92604e539b2114763150fb1ace60d28e59a889

Crashes occured immediately when clicking on "OpenGL render image" because there was only a task pool created previously when it was an animation. Solved it by introducing a variable is_animation to the openglrender and omitting the task_pool call when it's no animation.

@sergey: Please check my changes, moved the pool_ok and the lock into the is_animation clause.