apiserver/client: avoid unnecessary Mongo query
apiserver/client: avoid unnecessary Mongo query

Change NewClient to use State.EnvironUUID, instead
of State.Environment() and getting its UUID. The
former is cached in memory when State is opened.

Altoros/juju-cloudsigma,bz2/juju,Altoros/juju-cloudsigma,makyo/juju,waigani/juju,davecheney/juju,alesstimec/juju,mjs/juju,howbazaar/juju,mjs/juju,gabriel-samfira/juju,makyo/juju,kat-co/juju,frankban/juju-tmp,davecheney/juju,howbazaar/juju,bz2/juju,axw/juju,AdamIsrael/juju,dooferlad/juju,wwitzel3/juju,thomnico/juju,kat-co/juju,waigani/juju,bogdanteleaga/juju,ericsnowcurrently/juju,anastasiamac/juju,dimitern/juju,bac/juju,wwitzel3/juju,fwereade/juju,bogdanteleaga/juju,AdamIsrael/juju,Altoros/juju-cloudsigma,thomnico/juju,mikemccracken/juju,tsakas/juju,frankban/juju,dooferlad/juju,howbazaar/juju,tsakas/juju,axw/juju,mjs/juju,cherylj/juju,mhilton/juju,mjs/juju,cloud-green/juju,bogdanteleaga/juju,dimitern/juju,mhilton/juju-juju,bac/juju,perrito666/juju,anastasiamac/juju,mhilton/juju,mhilton/juju,tsakas/juju,thomnico/juju,ericsnowcurrently/juju,bac/juju,gabriel-samfira/juju,alesstimec/juju,axw/juju,marcmolla/juju,anastasiamac/juju,reedobrien/juju,gabriel-samfira/juju,mjs/juju,reedobrien/juju,alesstimec/juju,mjs/juju,waigani/juju,perrito666/juju,reedobrien/juju,voidspace/juju,mhilton/juju-juju,tsakas/juju,alesstimec/juju,perrito666/juju,dimitern/juju,frankban/juju-tmp,axw/juju,howbazaar/juju,mhilton/juju-juju,dimitern/juju,frankban/juju,makyo/juju,mjs/juju,anastasiamac/juju,cloud-green/juju,kat-co/juju,tych0/juju,voidspace/juju,wwitzel3/juju,howbazaar/juju,reedobrien/juju,davecheney/juju,cherylj/juju,frankban/juju,cherylj/juju,mikemccracken/juju,voidspace/juju,cherylj/juju,bac/juju,frankban/juju,fwereade/juju,macgreagoir/juju,frankban/juju,anastasiamac/juju,macgreagoir/juju,bac/juju,gabriel-samfira/juju,dooferlad/juju,dooferlad/juju,davecheney/juju,frankban/juju-tmp,thomnico/juju,bz2/juju,ericsnowcurrently/juju,bogdanteleaga/juju,cloud-green/juju,bz2/juju,tasdomas/juju,cloud-green/juju,tych0/juju,alesstimec/juju,ericsnowcurrently/juju,kat-co/juju,tych0/juju,marcmolla/juju,macgreagoir/juju,voidspace/juju,marcmolla/juju,reedobrien/juju,marcmolla/juju,waigani/juju,macgreagoir/juju,tasdomas/juju,marcmolla/juju,mikemccracken/juju,frankban/juju-tmp,bz2/juju,perrito666/juju,macgreagoir/juju,gabriel-samfira/juju,perrito666/juju,ericsnowcurrently/juju,mhilton/juju,mikemccracken/juju,dooferlad/juju,mikemccracken/juju,AdamIsrael/juju,Altoros/juju-cloudsigma,tasdomas/juju,AdamIsrael/juju,fwereade/juju,tych0/juju,mhilton/juju-juju,wwitzel3/juju,tasdomas/juju,kat-co/juju,fwereade/juju,dimitern/juju,axw/juju,makyo/juju