This patch removes Git.xs from the repository for the time being. This
should hopefully enable Git.pm to finally make its way to master.

Git.xs is not going away forever. When the Git libification makes some
progress, it will hopefully return (but most likely as an optional
component, due to the portability woes) since the performance boosts are
really important for applications like Gitweb or Cogito. It needs to go
away now since it is not really reliable in case you use it for several
repositories in the scope of a single process, and that is not possible
to fix without some either very ugly or very intrusive core changes.

Rest in peace. (While you can.)
Signed-off-by: NPetr Baudis <pasky@suse.cz>
Signed-off-by: NJunio C Hamano <junkio@cox.net>