Bug#722898: UI wording

[Thiemo Nagel <thiemo.nagel@gmail.com>]

Hello Christian,

> > Maybe "Skip" would be more precise than "Cancel"?
>
> You probably can't change this as the 'Cancel' button comes from the
> cdebconf interface.

I see. In this case, I agree with Gaudenz that we should explain what
"Cancel" means. I've given it a try:

"Overwriting ${DEVICE} with random data to prevent meta-information
leaks from the encrypted volume. This step may be skipped by pressing
'Cancel', albeit at the expense of a slight reduction of the quality
of the encryption."

Cheers,
Thiemo