git-remote-mediawiki: assign a variable as undef and make proper indentation

Explicitly assign local variable $/ as undef and make a proper
one-instruction-by-line indentation

Signed-off-by: Célestin Matte <celestin.matte@ensimag.fr>
Signed-off-by: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/mw-to-git/git-remote-mediawiki.perl

@@ -338,7 +338,10 @@ sub run_git {
 	my $args = shift;
 	my $encoding = (shift || "encoding(UTF-8)");
 	open(my $git, "-|:$encoding", "git " . $args);
-	my $res = do { local $/; <$git> };
+	my $res = do {
+		local $/ = undef;
+		<$git>
+	};
 	close($git);
 
 	return $res;