argv-array: add space after `while`

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

argv-array.c

@@ -46,7 +46,7 @@ void argv_array_pushl(struct argv_array *array, ...)
 	const char *arg;
 
 	va_start(ap, array);
-	while((arg = va_arg(ap, const char *)))
+	while ((arg = va_arg(ap, const char *)))
 		argv_array_push(array, arg);
 	va_end(ap);
 }