Fixes #2382, don't star journal entries from the object chooser

[Here is the ticket description](http://bugs.sugarlabs.org/ticket/2382)

>  In the objectchooser you can change the 'favorite' (star) property of a Journal entry.
>
> (don't think this has to be in the 0.90.0 release but might be worth to get in the update release)

It was a very weird bug since you would star the thing but the window would close straight away, leaving the users unaware that they just starred it.

I tried to use overriding callbacks but (a) couldn't get it to work and (b) kinda think that sort of oop can be really confusing.