Allow key value to be set when key is saved

Key for Drupal 7 currently has some fairly tight coupling of saving a key configuration (and key value) and the key provider with the key admin form. Decoupling them would require an API change, which is not really an option right now. I suggest that this issue be marked "Won't fix" and the programmatic saving of key values will just need to be done separately from the saving of the key configuration.