Allow git-svnimport to take "" as the trunk directory.
Allow git-svnimport to take "" as the trunk directory.

Some repositories started with the trunk in "/" and then moved it to the
standard "trunk/" location.

On these repositories, the correct thing would be to call git-svnimport -T "",
but because of the way the options are handled, it uses the default "trunk"
instead of the given empty string. This patch fixes that behaviour.

Reported by Leandro Lucarella <llucax@gmail.com>.

Signed-off-by: Alberto Bertogli <aa51a345a0e8173877757331a6c3833d48834cb6@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git