Add in estimate task when you make a sub-task

[Brandon Anderson]

When I make a sub-task before a sprint started, I can't seem to add in the estimate time. But when I start the sprint, I can then add in the estimate time.

All I want when I make a sub-task for a story, I can add in the estimate time right there 

[Steven F Behnke]

Add the Time Tracking field to the Create Screen for Subtasks.