Original estimate in planning board includes estimates from newly created stories

Original Estimate field get's updated if you create new issues in a sub-version in GreenHopper's planning board.

Steps to reproduce:

1. Go to GreenHopper's planning board
2. Create a version for your project
3. Set the "Start Date" to some day in the past
4. Create a few issues and a set time estimate for each one
5. Create a sub-version
6. Create an issue to the sub-version
7. See that both version and sub-version "Time Estimate" has changed. The Original Estimate shouldn't change after the version has started, so you don't loose your original metrics, newly created issues should count in "Remaining Estimate" (Time Remaining).

There is also another bug with time estimate, please see:

GHS-2467