(#284) Skip creation of HEAD branch

- Based on a suggestion from @nulltoken, skipping the creation of the HEAD branch, if it exists in the list of branches to create.
- This was causing an issue when running on AppVeyor
- This can be seen working here:
	https://ci.appveyor.com/project/GaryEwanPark/webapisample/build/0.2.0-unstable.23+23%20(Build%2034)