[packagekit] Adding support for "prepare" in transaction_flags

[Daniel Nicoletti]

2012/6/3 Matthias Klumpp <matthias at tenstral.net>:
> I really liked the suggestion for all stuff like RemovePackages()
> InstallPackages() etc. to just enqueue the actions and one new
> "Commit()" signal to really apply the changes.
> This would solve the issues, but to implement it properly, backend and
> frontend APIs would have to be broken, which is not ideal.
Well right now pretty much everything is broken, even the
install/remove/update methods, so creating this method would
imo bring some goodies, I can only tell by apt, but maybe
other backends could make use of that too.