git-svn: Set svn.authorsfile if it is passed to git svn clone

Signed-off-by: Alex Vandiver <alexmv@mit.edu>
Acked-by: Eric Wong <normalperson@yhbt.net>
diff --git a/git-svn.perl b/git-svn.perl
index eebcf0f..e927965 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -361,6 +361,7 @@
 	$path = basename($url) if !defined $path || !length $path;
 	cmd_init($url, $path);
 	Git::SVN::fetch_all($Git::SVN::default_repo_id);
+	command_oneline('config', 'svn.authorsfile', $_authors) if $_authors;
 }
 
 sub cmd_init {