Merge ~nteodosio/software-properties:initialize-pin into software-properties:ubuntu/master

[Nathan Teodosio]

    Initialize pin as empty string

    start_magic_attach is the only function that assigns a value to pin.
    If it can't retrieve it from the server, then it is uninitialized and
    selecting the pin radio button causes an error as update_state tries
    to use it (LP: #2004245).

[Sebastien Bacher (seb128)]

Thanks, that should at least fix the exception until we work on a proper solution to display an explanation to the user in those cases

review: Approve

diff --git a/softwareproperties/gtk/DialogUaAttach.py b/softwareproperties/gtk/DialogUaAttach.py
index 7a6af10..4959b14 100644
--- a/softwareproperties/gtk/DialogUaAttach.py
+++ b/softwareproperties/gtk/DialogUaAttach.py
@@ -38,6 +38,7 @@ class DialogUaAttach:
         self.contract_token = None
         self.attaching = False
         self.poll = None
+        self.pin = ""
 
         self.start_magic_attach()