The package solr installs and uses tomcat7.  Installing tomcat8 appears
to be a mistake for Debian Jessie.

The tomcat6 user doesn't have the right privileges to run the
/etc/init.d/tomcat6 script.  Removing these lines allows monit to
restart tomcat if it stops for any reason, and makes the tomcat6 monit
config more consistent with other monit configs elsewhere.