git-svn: use path accessor for Git::SVN objects

The accessors should improve maintainability and enforce
consistent access to Git::SVN objects.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
diff --git a/git-svn.perl b/git-svn.perl
index 0d77ffb..bd5266c 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -1314,7 +1314,7 @@
 	$path = $cmd_dir_prefix . $path;
 	fatal("No such file or directory: $path") unless -e $path;
 	my $is_dir = -d $path ? 1 : 0;
-	$path = join_paths($gs->{path}, $path);
+	$path = join_paths($gs->path, $path);
 
 	# canonicalize the path (otherwise libsvn will abort or fail to
 	# find the file)