ssh: enable GSSAPI and agent for kyriasis.com
git: write bitmap indexes when packing

Docs: "When true, git will write a bitmap index when packing all objects to
disk (e.g., when git repack -a is run). This index can speed up the "counting
objects" phase of subsequent packs created for clones and fetches, at the cost
of some disk space and extra time spent on the initial repack."