Update readme noting mongodb dependency change
Update readme noting mongodb dependency change

Now juju-core depends on a newer version of mongo than is present in the
archive, update README to remove it from the list of required packages and
instead suggest using the binaries from the public bucket.

R=fwereade, jameinel
CC=
https://codereview.appspot.com/7058050

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