Don't use attribute name if there is no help text

Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>

HISTORY.rst

@@ -8,6 +8,8 @@
 - Add targets to run staging containers using RabbitMQ as
   broker.
 - Add test for GitLab issue #702
+- Don't set SourceColumns to the attribute name when no help text
+  is defined.
 
 3.3.3 (2019-12-05)
 ==================

mayan/apps/navigation/classes.py

@@ -754,7 +754,7 @@ class SourceColumn(object):
                             name=name, model=model
                         )
                     except AttributeError:
-                        self._help_text = self.attribute
+                        self._help_text = None
 
         self.help_text = self._help_text