Unused files with double spaces in their name are not removed by `dropunused`:

Script:

    #!/bin/bash
    
    BASE=/tmp/unused-bug
    
    # setup
    set -x
    chmod -R +w $BASE
    rm -rf $BASE
    mkdir -p $BASE
    cd $BASE
    
    # create annex
    git init .
    git annex init
    
    # make a file with two spaces
    echo hello > 'foo  bar'
    
    # add it
    git annex add --backend WORM 'foo  bar'
    git commit -m 'add'
    
    # remove it
    git rm 'foo  bar'
    git commit -m 'remove'
    
    # unused
    git annex unused
    git annex dropunused 1
    git annex unused

Output:

    + chmod -R +w /tmp/unused-bug
    + rm -rf /tmp/unused-bug
    + mkdir -p /tmp/unused-bug
    + cd /tmp/unused-bug
    + git init .
    Initialized empty Git repository in /tmp/unused-bug/.git/
    + git annex init
    init  ok
    + echo hello
    + git annex add --backend WORM 'foo  bar'
    add foo  bar ok
    (Recording state in git...)
    + git commit -m add
    [master (root-commit) 926f7f5] add
     1 files changed, 1 insertions(+), 0 deletions(-)
     create mode 120000 foo  bar
    + git rm 'foo  bar'
    rm 'foo  bar'
    + git commit -m remove
    [master d025e3f] remove
     1 files changed, 0 insertions(+), 1 deletions(-)
     delete mode 120000 foo  bar
    + git annex unused
    unused . (checking for unused data...) (checking master...) 
      Some annexed data is no longer used by any files:
        NUMBER  KEY
        1       WORM-s6-m1322200438--foo  bar
      (To see where data was previously used, try: git log --stat -S'KEY')
      
      To remove unwanted data: git-annex dropunused NUMBER
      
    ok
    + git annex dropunused 1
    dropunused 1 ok
    + git annex unused
    unused . (checking for unused data...) (checking master...) 
      Some annexed data is no longer used by any files:
        NUMBER  KEY
        1       WORM-s6-m1322200438--foo  bar
      (To see where data was previously used, try: git log --stat -S'KEY')
      
      To remove unwanted data: git-annex dropunused NUMBER
      
    ok

Strange that `dropunused` still said "ok" when it didn't succeed at removing the file.

> It was misparsing the unused file, so it thought you'd asked it to drop a
> key that didn't exist (which means already dropped) so no error. I've
> fixed the bug. [[done]] --[[Joey]] 
