Fix python that broke the Lock Manager view in the Control Panel.

Fixes #651

doc/CHANGES.txt

@@ -32,6 +32,8 @@ Zope Changes
 
     Bugs Fixed
 
+      - Collector #651: WebDAV Lock Manager was broken.
+
       - Collector #646: metal:slot was lost during the I18n merge.
 
       - Removed the signal handler hung off USR1 for packing the database.

lib/python/App/dtml/davLockManager.dtml

@@ -25,7 +25,8 @@ function toggleSelect() {
 //-->
 </script>
 
-<dtml-let lockedobjs="REQUEST.form.has_key('frompath','') and findLockedObjects(frompath=REQUEST.get('frompath','')) or []">
+<dtml-let from_path="REQUEST.form.get('frompath',None)"
+          lockedobjs="from_path and findLockedObjects(frompath=from_path) or []">
 
 <dtml-if lockedobjs>
  <p class="std-text">All locked objects