readme: change shield color and remove tracking pixel

Signed-off-by: Sevki <s@sevki.org>

README.md

@@ -4,8 +4,7 @@ Harvey: A distributed operating system
 [![Build Status](https://travis-ci.org/Harvey-OS/harvey.svg?branch=master)](https://travis-ci.org/Harvey-OS/harvey)
 [![Coverity Badge](https://scan.coverity.com/projects/5328/badge.svg)](https://scan.coverity.com/projects/5328)
 [![License](https://img.shields.io/aur/license/yaourt.svg)](https://github.com/Harvey-OS/harvey/blob/master/LICENSE.gpl)
-[![Donate](https://img.shields.io/badge/Donate-PayPal-green.svg)](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=7Q45ZGJBQZZVN)
-<img alt="" border="0" src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" width="1" height="1">
+[![Donate](https://img.shields.io/badge/Donate-PayPal-brightgreen.svg)](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=7Q45ZGJBQZZVN)
 
 Welcome to Harvey, we are delighted that you are interested in the
 project.