Fnal cms eos

Hey Ted,

The original idea of adding the eos directory as the value of eosPrefix key didn't quite work since the funcion which lists the files invoked "eos ls -l "+location   and not "eos ls -l "+ eosPrefix + localtion.

In any case, the other simple solution was to replicate what we did for dCache and add a trim.

The changes tested successful, and as far as I can tell the atlas configuration would still work since eosTrim is set to "" as default. 

Y.