provider/azure: ensure tests work correctly
provider/azure: ensure tests work correctly

Some tests I wrote call StartInstance to
check the parameters passed to createInstance.
The tests don't actually verify that it called
that method successfully, and all validation
is done within the method. Updated the tests
to ensure from outside that the method is called.

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