ERP5Type.patches.sqltest: Fix "optional" support when using expression.

expr(md) raises NameError when expr references a non-given argument, so
catch that exception too. (sqlvar catches Exception, which seems overkill,
so don't follow it)

product/ERP5Type/patches/sqltest.py

@@ -28,7 +28,7 @@ if 1: # For easy diff with original
                 v=md[expr]
             else:
                 v=expr(md)
-        except KeyError:
+        except (KeyError, NameError):
             if args.has_key('optional') and args['optional']:
                 return ''
             raise ValueError, 'Missing input variable, <em>%s</em>' % name