Fix LDAP issue with legal entities: 'sn' cannot be empty

coin/members/models.py

@@ -213,8 +213,12 @@ class Member(CoinLdapSyncMixin, AbstractUser):
             ldap_user.nick_name = self.username
             ldap_user.uidNumber = uid_number
 
-        ldap_user.last_name = self.last_name
-        ldap_user.first_name = self.first_name
+        if self.type == 'natural_person':
+            ldap_user.last_name = self.last_name
+            ldap_user.first_name = self.first_name
+        elif self.type == 'legal_entity':
+            ldap_user.last_name = self.organization_name
+            ldap_user.first_name = ""
 
         # If a password is definied in _password_ldap, change it in LDAP
         if self._password_ldap: