Added an explanation about how to upgrade the database version schema and fixtures, both
from the developer point of view and from the sysadmin point of view.
When run without any parameter, show a help message to leave clear that it's not doing anything
Remove the deploy call that was making upgradedb.
Fix an issue with upgradedb that was making it fail when run with
--prepare_upgrade and no database instance (which shouldn't be needed,
and now isn't)
upgradedb now shows the help message if run without parameters
Remove empty spaces at the end of some lines