Clean up Tomcat 6 note from build docs
Clean up Tomcat 6 note from build docs

Looking at https://github.com/cBioPortal/cbioportal/pull/3267,
I gather that suggesting to run the current release on Tomcat 6
would probably just result in a bad first impression when
the newer code doesn't work.
mandawilson/cbioportal,angelicaochoa/cbioportal,angelicaochoa/cbioportal,angelicaochoa/cbioportal,n1zea144/cbioportal,n1zea144/cbioportal,mandawilson/cbioportal,pughlab/cbioportal,angelicaochoa/cbioportal,pughlab/cbioportal,onursumer/cbioportal,onursumer/cbioportal,cBioPortal/cbioportal,mandawilson/cbioportal,onursumer/cbioportal,n1zea144/cbioportal,pughlab/cbioportal,zhx828/cbioportal,sheridancbio/cbioportal,zhx828/cbioportal,d3b-center/pedcbioportal,cBioPortal/cbioportal,sheridancbio/cbioportal,angelicaochoa/cbioportal,pughlab/cbioportal,n1zea144/cbioportal,d3b-center/pedcbioportal,sheridancbio/cbioportal,onursumer/cbioportal,onursumer/cbioportal,mandawilson/cbioportal,zhx828/cbioportal,d3b-center/pedcbioportal,onursumer/cbioportal,d3b-center/pedcbioportal,zhx828/cbioportal,n1zea144/cbioportal,mandawilson/cbioportal,cBioPortal/cbioportal,zhx828/cbioportal,sheridancbio/cbioportal,zhx828/cbioportal,sheridancbio/cbioportal,n1zea144/cbioportal,zhx828/cbioportal,sheridancbio/cbioportal,cBioPortal/cbioportal,cBioPortal/cbioportal,n1zea144/cbioportal,pughlab/cbioportal,pughlab/cbioportal,d3b-center/pedcbioportal,mandawilson/cbioportal,cBioPortal/cbioportal,angelicaochoa/cbioportal,pughlab/cbioportal,mandawilson/cbioportal,d3b-center/pedcbioportal,angelicaochoa/cbioportal,d3b-center/pedcbioportal