git-svn: convert 'init' to use Git::SVN
git-svn: convert 'init' to use Git::SVN

While we're at it, fix up some bugs in Git::SVN.

Signed-off-by: Eric Wong <8c2951295f8292b0c03727bc4652981172298eae@yhbt.net>

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