Add default branch to .gitreview for icehouse branch

This will cause git review to do the right thing when people try to
submit patches to this branch.

Change-Id: I2d1ef480404f82e0c227ba9838d43cac040adc6b
Remove hardcoded version.

We use semantic versioning, not pbr's pre-version facility. This
line causes local package builds to have the wrong version, and
pbr will in future detect this and error.

Change-Id: Iff26a28a48a7b14df82df06eb102af539c367c39