Couple fixes for my previous commit:
- In some cases smoke flow could have 1 cell clipped off its sides.
- Forgot to re-enable openmp for emission code.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56669 954f8c5b-7b00-dc11-b283-0030488c597c