patch nag: Fix some bookmark window glitches

[Christian Neumair <cneumair gnome org>]

http://bugzilla.gnome.org/show_bug.cgi?id=318278

This patch ensures that the old selection is restored when repopulating
the bookmark list, and that changes in the text field are written back
before the tree selection is changed.

Due to my implementation we don't account for programmatical changes to
the tree selection, which is IMO a good thing. Otherwise an update
triggered by other applications could cause a write-reread cycle. This
could revert the bookmark changes and write half-modified entry data to
disk.

best regards,
 Christian Neumair

-- 
Christian Neumair <cneumair gnome org>