bzr status: hiding shelf info if files are specified

[Eli Zaretskii]

> From: Martin Pool <mbp at sourcefrog.net>
> Date: Fri, 18 Nov 2011 13:32:59 +1100
> Cc: Francis Devereux <francis at devrx.org>, bazaar at lists.canonical.com, 
> 	robertc at robertcollins.net
> 
> Checking the shelf for changes to a particular file could be a useful
> separate feature

E.g., make "bzr shelve --list -v" actually "display more information" ;-)