git-svn - return original format_svn_date semantics

When %z was removed from the strftime call and subsituted with a
local gmt offset calculation, time() was no longer the default for
all time functions as it was with the previous localtime(shift).
This is now corrected so that format_svn_time behaves as it used to.

Signed-off-by: Ben Walton <bwalton@artsci.utoronto.ca>
Acked-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/git-svn.perl b/git-svn.perl
index a676a4c..959eb52 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -4738,7 +4738,7 @@
 
 sub format_svn_date {
 	# some systmes don't handle or mishandle %z, so be creative.
-	my $t = shift;
+	my $t = shift || time;
 	my $gm = timelocal(gmtime($t));
 	my $sign = qw( + + - )[ $t <=> $gm ];
 	my $gmoff = sprintf("%s%02d%02d", $sign, (gmtime(abs($t - $gm)))[2,1]);