README.md: add Coverity scan status badge

Author: zonque

README.md

@@ -1,6 +1,7 @@
 # systemd - System and Service Manager
 
-[![Build Status](https://semaphoreci.com/api/v1/projects/28a5a3ca-3c56-4078-8b5e-7ed6ef912e14/443470/shields_badge.svg)](https://semaphoreci.com/systemd/systemd)
+[![Build Status](https://semaphoreci.com/api/v1/projects/28a5a3ca-3c56-4078-8b5e-7ed6ef912e14/443470/shields_badge.svg)](https://semaphoreci.com/systemd/systemd)<br/>
+[![Coverity Scan Status](https://scan.coverity.com/projects/350/badge.svg)](https://scan.coverity.com/projects/350)
 
 ## Details