I noticed while testing that when you remove tomcat7/tomcat8 that it doesn't remove all of the directories. The log directory is expected since it contains files that aren't installed by the RPM, but the other directories that are left empty should also be removed. List:

# find / -name tomcat8 | grep -v log
/usr/share/selinux/packages/tomcat8
/usr/share/java/tomcat8
/usr/share/tomcat8