Merge r80451 from trunk

doc/CHANGES.txt

@@ -8,6 +8,9 @@ Zope Changes
 
    Bugs fixed
 
+      - Launchpad #147201: treat container-class in zope.conf as a string,
+        making it possible to use types from extra products directories.
+
       - Collector #2287: form ':record' objects did not implement enough
         of the mapping protocol.
 

lib/python/Zope2/Startup/zopeschema.xml

@@ -236,7 +236,7 @@
       </description>
     </key>
 
-    <key name="container-class" datatype=".python_dotted_path">
+    <key name="container-class" datatype="string">
       <description>
        Change the contiainer class a (mounted) database uses on a
        per-database basis to support a different container than a plain