Fix a couple bugs in AddAvailabilityZoneToInstanceData.
Fix a couple bugs in AddAvailabilityZoneToInstanceData.

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