Missing options in Journal batch copy palette

[tch]

The palette for batch copy-to, in the Journal, doesn't show options for external volumes.

To reproduce:

1. Boot the laptop with the memory stick plugged in.
2. Once in Sugar, go to the Journal.
3. Select any entry to activate the batch operations toolbar.
4. Click on the batch copy-to icon.

Outcome:
You should see no options for the memory stick.

Some clues:
if go to volumes or documents view and go back, then the option appears.

[tch]

On sugar-build, it can be reproduced by first entering to the journal and then plugging the memory stick.

I am sending a pull request now.

[Martin Abente Lahaye]

Fix missing options in batch copy palette

Its too early for using CopyMenuBuilder, wait until
the palette its propely initialized.

I do not fully understand why this is happening.
My only guess is that there could be some async
stuff happening between the constructor and callback.

Fixes #4718

Signed-off-by: Martin Abente Lahaye <tch@…>

Changeset: 87d3199c0ec6ed53cb1c5b2b0e069a442c3ab648