Initial addition of a password entry dialog. Looks like:
+------------------------------------------------+
| LUKS Passphrase /dev/sdb1 |
+------------------------------------------------+
| Enter LUKS passphrase to open /dev/sdb1 |
| Passphrase: [ ] |
| |
| [ Cancel ] [ Unlock ] |
+------------------------------------------------+
A standard Gtk Dialog is used to accept the password once, with any
errors displayed in a separate error dialog afterwards. This is poor UI
design. A password dialog should remain open for all authentication
attempts and only close when successful or the dialog is cancelled or
closed. This UI design issue will be improved in following commits.
Bug 795617 - Implement opening and closing of LUKS mappings
Mike Fleetwood