fix a possible error when solver action is not set

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@45810 20353a03-c40f-0410-a6d1-a30d3c3de9de

bt5/erp5_simulation/SkinTemplateItem/portal_skins/erp5_simulation/QuantitySplitSolver_viewConfigurationFormBox/my_delivery_solver.xml

@@ -157,7 +157,7 @@
       <dictionary>
         <item>
             <key> <string>_text</string> </key>
-            <value> <string>python:[(here.Base_translateString(x.getSolverActionTitle()), x.getId()) for x in cell.searchDeliverySolverList()]</string> </value>
+            <value> <string>python:[(here.Base_translateString(x.getSolverActionTitle() or \'\'), x.getId()) for x in cell.searchDeliverySolverList()]</string> </value>
         </item>
       </dictionary>
     </pickle>

bt5/erp5_simulation/bt/revision

-154
\ No newline at end of file
+155
\ No newline at end of file