Fix bug.

lib/tasks/copy_site.rake

@@ -98,6 +98,7 @@ namespace :create_site do
         extensions = ["downloaded_extensions.rb","built_in_extensions.rb"]
         extensions.each do |extension_file|
             outputs = exec_ssh_command_by_sudo_for_create(ssh,"cat #{args.path}/#{@site_construct.get_site_name}/#{extension_file}")
+            next if outputs.blank?
             if !outputs.include?("No such file or directory")
                 read_lines = outputs.split("\n").map{|l| l.split('#').first}
                 include_path_lines = read_lines.select{|l| l.include?("path")}