fix broken ssh public key handling

- make sure that AddSshPublicKeyForm does not try to parse the key if it is
  None
- split the key text into a maximum of 3 parts to allow whitespace in comments
- update changelog

gnuviechadmin/osusers/models.py

@@ -528,9 +528,9 @@ class SshPublicKeyManager(models.Manager):
             if 'comment' in headers:
                 comment = headers['comment']
         else:
-            parts = keytext.split()
-            if len(parts) > 3:
-                raise ValueError("unsupported key format")
+            parts = keytext.split(None, 2)
+            if len(parts) < 2:
+                raise ValueError('invalid SSH public key')
             data = parts[1]
             comment = len(parts) == 3 and parts[2] or ""
         keybytes = base64.b64decode(data)