commitablefilectx: move __nonzero__ from workingfilectx

mercurial/context.py

@@ -1202,6 +1202,9 b' class commitablefilectx(basefilectx):'
         if ctx:
             self._changectx = ctx
 
+    def __nonzero__(self):
+        return True
+
 class workingfilectx(commitablefilectx):
     """A workingfilectx object makes access to data related to a particular
        file in the working directory convenient."""
@@ -1212,9 +1215,6 b' class workingfilectx(commitablefilectx):'
     def _changectx(self):
         return workingctx(self._repo)
 
-    def __nonzero__(self):
-        return True
-
     def data(self):
         return self._repo.wread(self._path)
     def renamed(self):