Issue:
uninstall script for PowerChute Network Shutdown 4.2 and above does not properly clean up firewalld on RHEL 7.3 and above and CentOS 7.3 and above. 

Product:
PowerChute Network Shutdown version 4.2, and above

Environment:
RHEL 7.3 and CentOS 7.3

Cause:
From RHEL 7.3 release notes, firewalld packages have been upgraded to provide some enhancements over its previous version. Which includes changes in the firewall-cmd, firewall-offline-cmd, firewall-config, and firewall-applet.

Solution:
After running the PowerChute uninstall script run the command 

firewall-cmd --remove-service=pcns --permanent