Fix for emails with empty body

lib/email/message_builder.rb

@@ -7,7 +7,9 @@ module Email
       builder = Email::MessageBuilder.new(*builder_args)
       headers(builder.header_args) if builder.header_args.present?
       mail(builder.build_args).tap { |message|
-        message.html_part = builder.html_part if message
+        if message and h = builder.html_part
+          message.html_part = h
+        end
       }
     end
   end

lib/email/sender.rb

@@ -39,7 +39,7 @@ module Email
         end
       end
 
-      @message.parts[0].body = @message.parts[0].body.to_s.gsub!(/\[\/?email-indent\]/, '')
+      @message.parts[0].body = @message.parts[0].body.to_s.gsub(/\[\/?email-indent\]/, '')
 
       @message.text_part.content_type = 'text/plain; charset=UTF-8'