fix issues when rpm -e was used to remove older packages

I was getting an error when I did:

[shin4590@shinta-rhel1g-ah1 webapps]$ sudo rpm -e atomhopper-1.2.6-1 --verbose
rm: cannot remove `/srv/tomcat/webapps/ROOT/': Not a directory
error: %postun(atomhopper-1.2.6-1.noarch) scriptlet failed, exit status 1

The problem was /srv/tomcat/webapps/ROOT is a soft link to /src/tomcat7/webapps/ATOMHOPPER. Since anyway we explicitly depend on tomcat7 in pom.xml:

                                <require>tomcat7</require>

I think it should be ok to add this change.