The bug is in JWS3 Tomcat7 and Tomcat8

Description of problem:
The /etc/init.d/tomcat script is not constructed to handle a user with a name that does not correspond to an existing group

Steps to Reproduce:
1. Create a user (such as "test") on a system where the group "test" does not exist. For example, create with test:test1 configuration
2. Change the /etc/sysconfig/tomcat with TOMCAT_USER=test
3. Start /etc/init.d/tomcat6

Actual results:
The chown of the CATALINA_PID file failed
The tomcat can't write to the CATALINA_PID file
It is impossible to stop tomcat with /etc/init.d/tomcat stop

Expected results:
The chown is done correctly and the start/stop of tomcat is operationnal

See BZ: https://bugzilla.redhat.com/show_bug.cgi?id=915447