git-svn: fix cloning of HTTP URLs with '+' in their path

With this, git svn clone -s http://svn.gnome.org/svn/gtk+
is successful.

Also modified the funky rename test for this, which _does_
include escaped '+' signs for HTTP URLs.  SVN seems to accept
either "+" or "%2B" in filenames and directories (just not the
main URL), so I'll leave it alone for now.

Signed-off-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 e47b1ea..413e0b1 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -3673,7 +3673,7 @@
 	my ($uri) = @_;
 	my @tmp;
 	foreach (split m{/}, $uri) {
-		s/([^\w.%-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
+		s/([^\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
 		push @tmp, $_;
 	}
 	join('/', @tmp);