Merge from 2_6 branch.

PageTemplateFiles were previously owned by whatever object contained
them.  This resulted in very hard bugs if the user who owned the
container was removed.  Since PageTemplateFiles come from the
filesystem, they are now "unowned", similar to DTMLFiles.  Security is
still applied, but now it is applied correctly.

lib/python/Products/PageTemplates/PageTemplateFile.py

@@ -15,7 +15,7 @@
 Zope object encapsulating a Page Template from the filesystem.
 """
 
-__version__='$Revision: 1.21 $'[11:-2]
+__version__='$Revision: 1.22 $'[11:-2]
 
 import os, AccessControl, Acquisition, sys
 from Globals import package_home, DevelopmentMode
@@ -139,6 +139,15 @@ class PageTemplateFile(Script, PageTemplate, Traversable):
 
     __roles__ = ComputedAttribute(_get__roles__, 1)
 
+    def getOwner(self, info=0):
+        """Gets the owner of the executable object.
+
+        This method is required of all objects that go into
+        the security context stack.  Since this object came from the
+        filesystem, it is owned by no one managed by Zope.
+        """
+        return None
+
     def __getstate__(self):
         from ZODB.POSException import StorageError
         raise StorageError, ("Instance of AntiPersistent class %s "