cmd/juju/service: clarify the meaning of the "default" field in the "get" output
cmd/juju/service: clarify the meaning of the "default" field in the "get" output

Fixes LP #1496639.

cloud-green/juju,bac/juju,macgreagoir/juju,voidspace/juju,waigani/juju,mjs/juju,frankban/juju,davecheney/juju,mikemccracken/juju,alesstimec/juju,reedobrien/juju,ericsnowcurrently/juju,dooferlad/juju,macgreagoir/juju,howbazaar/juju,perrito666/juju,frankban/juju,dooferlad/juju,ericsnowcurrently/juju,marcmolla/juju,bac/juju,makyo/juju,alesstimec/juju,reedobrien/juju,AdamIsrael/juju,alesstimec/juju,bz2/juju,waigani/juju,frankban/juju,makyo/juju,wwitzel3/juju,alesstimec/juju,bz2/juju,kat-co/juju,mjs/juju,anastasiamac/juju,gabriel-samfira/juju,perrito666/juju,bogdanteleaga/juju,makyo/juju,ericsnowcurrently/juju,axw/juju,bac/juju,bogdanteleaga/juju,makyo/juju,davecheney/juju,wwitzel3/juju,anastasiamac/juju,bz2/juju,mjs/juju,mjs/juju,fwereade/juju,fwereade/juju,axw/juju,dimitern/juju,gabriel-samfira/juju,reedobrien/juju,marcmolla/juju,howbazaar/juju,kat-co/juju,cloud-green/juju,davecheney/juju,davecheney/juju,kat-co/juju,anastasiamac/juju,dimitern/juju,bz2/juju,reedobrien/juju,dimitern/juju,bac/juju,waigani/juju,frankban/juju,anastasiamac/juju,mjs/juju,fwereade/juju,mjs/juju,ericsnowcurrently/juju,dooferlad/juju,marcmolla/juju,macgreagoir/juju,macgreagoir/juju,marcmolla/juju,waigani/juju,mikemccracken/juju,mikemccracken/juju,perrito666/juju,mjs/juju,wwitzel3/juju,ericsnowcurrently/juju,marcmolla/juju,howbazaar/juju,bogdanteleaga/juju,anastasiamac/juju,cloud-green/juju,howbazaar/juju,mikemccracken/juju,fwereade/juju,mikemccracken/juju,AdamIsrael/juju,voidspace/juju,AdamIsrael/juju,kat-co/juju,axw/juju,perrito666/juju,voidspace/juju,bac/juju,alesstimec/juju,dimitern/juju,gabriel-samfira/juju,AdamIsrael/juju,bz2/juju,reedobrien/juju,wwitzel3/juju,dimitern/juju,axw/juju,voidspace/juju,dooferlad/juju,gabriel-samfira/juju,howbazaar/juju,axw/juju,macgreagoir/juju,perrito666/juju,gabriel-samfira/juju,frankban/juju,cloud-green/juju,dooferlad/juju,bogdanteleaga/juju,kat-co/juju