Products.ExternalEditor: stick to version 1.x.

because Products.ExternalEditor 2.0.0's dtml is not based on Zope2
OFS's one and it drops icons, sort by last_modified etc in ZMI.

stack/erp5/buildout.cfg

@@ -672,7 +672,8 @@ zope.app.testing = 3.8.1
 Pillow = 3.2.0
 Products.CMFActionIcons = 2.1.3
 Products.DCWorkflowGraph = 0.4.1
-Products.ExternalEditor = 2.0.0
+# Products.ExternalEditor 2.0.0's dtml is not based on Zope2 OFS's one.
+Products.ExternalEditor = 1.1.1
 Products.GenericSetup = 1.8.3
 Products.LongRequestLogger = 2.0.0
 Products.MimetypesRegistry = 2.0.8