apt-get upgrade misconfigured and does not run

[Martin Packman]

The following cloud config options are supplied by juju when setting up a machine:

    apt-update: true
    apt-upgrade: true

Unfortunately cloud-init ignores these completely, as they are misspellings of 'apt_update' and 'apt_upgrade'. In practice, the update is run anyway as juju supplies the 'packages' key which requires it, but upgrade is never run.

Either the erroneous keys should be removed, or corrected so that the intended commands are run on machine startup. The go port of juju does use the correct spellings.