ui change for file-roller

[Paolo Bacchilega <paolo bacchilega libero it>]

Hello,

I changed the file-roller extract dialog removing the password entry.
The reason is that the dialog is already full of options and the 
password entry is redundant because if the archive is encrypted the 
password will be requested during the extraction.

I've updated the "extract options" section of the user's manual too.


Ciao,
Paolo.