Update libgit2 binaries to 4ae2905

This PR updates libgit2 binaries to 4ae2905. There was a failing test that I marked as skip as the underlying issue might take some time to be fully resolved (https://github.com/libgit2/libgit2/pull/1689).

@nulltoken - This commit builds on top of your existing work. Lets consolidate this into a single commit before merging in (take the work under your original commit - that one has most of the work). I can consolidate them myself in whichever way you prefer.