fix password issue #2097

lib/wallet.py

@@ -1656,6 +1656,7 @@ class Multisig_Wallet(Deterministic_Wallet):
 
     def update_password(self, old_pw, new_pw):
         for name, keystore in self.keystores.items():
+            if keystore.can_change_password():
                 keystore.update_password(old_pw, new_pw)
                 self.storage.put(name, keystore.dump())
         self.storage.put('use_encryption', (new_pw is not None))