[meld] Update get_commits_to_push_summary to raise NotImplementedError

[Kai Willadsen <kaiw src gnome org>]

commit a995a5127a6950c42b43ac590796c297661f7325
Author: Louis des Landes <louis obsidian com au>
Date:   Wed Jun 12 11:59:18 2013 +1000

    Update get_commits_to_push_summary to raise NotImplementedError
    
    https://bugzilla.gnome.org/show_bug.cgi?id=702052

 meld/vc/_vc.py |    3 +++
 meld/vcview.py |    2 +-
 2 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/meld/vc/_vc.py b/meld/vc/_vc.py
index 23effff..e7590af 100644
--- a/meld/vc/_vc.py
+++ b/meld/vc/_vc.py
@@ -163,6 +163,9 @@ class Vc(object):
 
     def revert(self, runner, files):
         raise NotImplementedError()
+    
+    def get_commits_to_push_summary(self):
+        raise NotImplementedError()
 
     def remove(self, runner, files):
         raise NotImplementedError()
diff --git a/meld/vcview.py b/meld/vcview.py
index f70fb5e..c62f8a3 100644
--- a/meld/vcview.py
+++ b/meld/vcview.py
@@ -495,7 +495,7 @@ class VcView(melddoc.MeldDoc, gnomeglade.Component):
                 col = self.model.column_index(COL_OPTIONS, 0)
                 self.model.set_value(root, col,
                                      self.vc.get_commits_to_push_summary())
-            except AttributeError:
+            except NotImplementedError:
                 pass
 
             self.scheduler.add_task(self._search_recursively_iter(root))