[0.14] improve bzr rm + bzr revert combination

[Jari Aalto]

Consider this:

    $ bzr rm control
    <..oops, not that one>
    $ bzr revert     
    Conflict adding file control.  Moved existing file to control.moved.

SUGGESTION

I think the above can be avoided alltogether.

bzr could check if the file was not modified when it is about to
restore file back to the original location.

    - Generate m5sum of file on disk
    - compare to md5sum of file in repository
    => if they match just change file status back to "versioned"

Jari