git-svn: quiet some warnings when run only with --version/--help

These are harmless but annoying.  They were introduced in
512b620bd9fef7f170562ecad835e37479f051ce

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/git-svn.perl b/git-svn.perl
index 7ebd07b..4d3c453 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -168,14 +168,14 @@
 my %opts = %{$cmd{$cmd}->[2]} if (defined $cmd);
 
 read_repo_config(\%opts);
-Getopt::Long::Configure('pass_through') if $cmd eq 'log';
+Getopt::Long::Configure('pass_through') if ($cmd && $cmd eq 'log');
 my $rv = GetOptions(%opts, 'help|H|h' => \$_help, 'version|V' => \$_version,
                     'minimize-connections' => \$Git::SVN::Migration::_minimize,
                     'id|i=s' => \$Git::SVN::default_ref_id,
                     'svn-remote|remote|R=s' => sub {
                        $Git::SVN::no_reuse_existing = 1;
                        $Git::SVN::default_repo_id = $_[1] });
-exit 1 if (!$rv && $cmd ne 'log');
+exit 1 if (!$rv && $cmd && $cmd ne 'log');
 
 usage(0) if $_help;
 version() if $_version;