Fixstates only after Z-Push upgrade

[matidau]

This is to only run z-push-admin -a fixstates after a Z-Push upgrade.

I've checked and the configuration in zpush.sh won't affect the state files.

This will alleviate the problem raised on the forums when there is an upgrade without a Z-Push upgrade. https://discourse.mailinabox.email/t/problems-with-z-push-mail-sync-after-each-upgrade-of-miab/12145