support cases when brain.total_price is None

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@11344 20353a03-c40f-0410-a6d1-a30d3c3de9de

bt5/erp5_accounting/SkinTemplateItem/portal_skins/erp5_accounting/Movement_getCreditPrice.xml

@@ -68,7 +68,7 @@
         </item>
         <item>
             <key> <string>_body</string> </key>
-            <value> <string>return -min(brain.total_price, 0)\n
+            <value> <string>return max(-(brain.total_price or 0), 0)\n
 </string> </value>
         </item>
         <item>
@@ -120,7 +120,7 @@
                             <string>brain</string>
                             <string>selection</string>
                             <string>kwd</string>
-                            <string>min</string>
+                            <string>max</string>
                             <string>_getattr_</string>
                           </tuple>
                         </value>

bt5/erp5_accounting/bt/revision

-129
\ No newline at end of file
+130
\ No newline at end of file