git-clone: Keep remote names when cloning unless explicitly told not to.

git-clone: Keep remote names when cloning unless explicitly told not to.

With this patch the following commands all clone into the local directory
"repo". If repo exists, it will still barf.

	git-clone git://host.xz/repo.git
	git-clone /path/to/repo/.git
	git-clone host.xz:repo.git

I ended up doing the same source-to-target sed'ing for all our company
projects, so it was easier to add it directly to git-clone.

Signed-off-by: Andreas Ericsson <ae@op5.se>
Signed-off-by: Junio C Hamano <junkio@cox.net>