bump libgit2 to 90431f
bump libgit2 to 90431f

Acidburn0zzz/rugged,libgit2/rugged,Acidburn0zzz/rugged,saraid/rugged,tpickett66/rugged,Acidburn0zzz/rugged,libgit2/rugged,saraid/rugged,spraints/rugged,spraints/rugged,tpickett66/rugged,libgit2/rugged,saraid/rugged,tpickett66/rugged