Merged [7924] from rcross@amsl.com: allow no IPR license selection on update.

 - Legacy-Id: 7931
Note: SVN reference [7924] has been migrated to Git commit 3738650

Author: levkowetz

ietf/ipr/models.py

@@ -6,6 +6,7 @@
 
 
 LICENSE_CHOICES = (
+    (0, ''),
     (1, 'a) No License Required for Implementers.'),
     (2, 'b) Royalty-Free, Reasonable and Non-Discriminatory License to All Implementers.'),
     (3, 'c) Reasonable and Non-Discriminatory License to All Implementers with Possible Royalty/Fee.'),