[meld] Fix darcs traceback in a repository with no

[Vincent Legoll <vincele src gnome org>]

commit fec3db7e63513e025680b796207bed7a1650a0e2
Author: Vincent Legoll <vincent legoll gmail com>
Date:   Fri May 1 12:16:16 2009 +0200

    Fix darcs traceback in a repository with no
    changes, for example like an empty repository.
    
    Reproduce with:
    - cd /tmp
    - mkdir darcsempty
    - cd darcsempty
    - meld .
    
    Traceback (most recent call last):
      File "/home/vince/dev/git/meld/task.py", line 130, in iteration
        ret = task()
      File "/home/vince/dev/git/meld/vcview.py", line 290, in _search_recursively_iter
        self.vc.cache_inventory(rootname)
      File "/home/vince/dev/git/meld/vc/_vc.py", line 177, in cache_inventory
        self._tree_cache = self._lookup_tree_cache(directory)
      File "/home/vince/dev/git/meld/vc/darcs.py", line 83, in _lookup_tree_cache
        non_boring = self._get_whatsnew()
      File "/home/vince/dev/git/meld/vc/darcs.py", line 110, in _get_whatsnew
        status = self.state_map[elements.pop(0)]
    KeyError: 'No'
---
 vc/darcs.py |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/vc/darcs.py b/vc/darcs.py
index f480000..9d22cb1 100644
--- a/vc/darcs.py
+++ b/vc/darcs.py
@@ -101,6 +101,8 @@ class Vc(_vc.CachedVc):
                 if e.errno != errno.EAGAIN:
                     raise
         for line in p:
+            if line.startswith('No changes!'):
+                continue
             elements = line.split()
             if len(elements) > 1:
                 if elements[1] == '->':