Revert "Updated to Git version 2.2.1"
This reverts commit 19df0d016ea9bfa3193a4eaafa2ff9702dae0312.
I decided to revert this as building git from source increases the image size by over 1GB, taking the total to almost 2GB which isn't acceptable.  Therefore until I have good reason to use anything other than 1.8.3 which is included in base it'll stay as that.