[pitivi] project: Remove unused code from _emitChange

[Alexandru Băluț <alexbalut src gnome org>]

commit b3417272da48d104b809e084743e047955758be3
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Tue May 31 17:45:10 2016 +0200

    project: Remove unused code from _emitChange
    
    Differential Revision: https://phabricator.freedesktop.org/D1041

 pitivi/project.py |    8 +++-----
 1 files changed, 3 insertions(+), 5 deletions(-)
---
diff --git a/pitivi/project.py b/pitivi/project.py
index a1eb373..d116c41 100644
--- a/pitivi/project.py
+++ b/pitivi/project.py
@@ -1467,11 +1467,9 @@ class Project(Loggable, GES.Project):
             self._has_default_audio_settings = False
             self.emit("settings-set-from-imported-asset", asset)
 
-    def _emitChange(self, signal, key=None, value=None):
-        if key and value:
-            self.emit(signal, key, value)
-        else:
-            self.emit(signal)
+    def _emitChange(self, signal, key, value):
+        self.emit(signal, key, value)
+        # TODO: Remove this when it's possible to undo/redo these changes.
         self.setModificationState(True)
 
     def _getElementFactoryName(self, elements, profile):