### Please describe the problem.
Changing metadata while being in an active view will not update the view.

### What steps will reproduce the problem?
(inside a repository)

1. Create a file

        $ uuidgen >file

2. switch into a view

       $ git annex view !blah
       $ ls
       file

3. changed the metadata the view is based upon

       $ git annex metadata -t blah file
       $ ls
       file

   It would be nice/expected that the view gets updated when the metadata changes, hiding 'file' now
  

### What version of git-annex are you using? On what operating system?

git-annex version: 5.20141024~bpo70+1
on debian wheezy with backports

### Please provide any additional information below.
