builder: Supply builder take into account from_date parameter

bt5/erp5_base/MixinTemplateItem/portal_components/mixin.erp5.BuilderMixin.py

@@ -298,7 +298,7 @@ class BuilderMixin(XMLObject, Amount, Predicate):
       group_by_node=1, allow_intermediate_negative_stock=True,
       **kw):
     portal = self.getPortalObject()
-    if not from_date:
+    if from_date is None:
       from_date = DateTime().earliestTime()
 
     # Initiate Conditions taken from Yusei T. Original Script