git-svn: Set svn.authorsfile to an absolute path when cloning

If --authors-file is passed a relative path, cloning will work, but
future `git svn fetch`es will fail to locate the authors file
correctly.  Thus, use File::Spec->rel2abs to determine an absolute
path for the authors file before setting it.

Signed-off-by: Alex Vandiver <alex@chmrr.net>
Acked-by: Eric Wong <normalperson@yhbt.net>

git-svn.perl

@@ -392,9 +392,11 @@ sub cmd_clone {
 		$path = $url;
 	}
 	$path = basename($url) if !defined $path || !length $path;
+	my $authors_absolute = $_authors ? File::Spec->rel2abs($_authors) : "";
 	cmd_init($url, $path);
 	Git::SVN::fetch_all($Git::SVN::default_repo_id);
-	command_oneline('config', 'svn.authorsfile', $_authors) if $_authors;
+	command_oneline('config', 'svn.authorsfile', $authors_absolute)
+	    if $_authors;
 }
 
 sub cmd_init {