Changing country and then selecting a province returns error "An illegal choice has been detected. Please contact the site administrator."

Problem/Motivation

• Enable either the location_node module or the location_cck module
• Set up a country field and province field in a content type
• Create a new node and select a country (e.g. UK) and a province (e.g. Cheshire) and save the node
• Edit the node, change the country (e.g. Canada), select a new province (e.g. Prince Edward Island)
• Save the node - you should get an error message: "An illegal choice has been detected. Please contact the site administrator.".

Proposed resolution

Line 283 in location.module in function _location_expand_location() checks if ['value']['country'] is set on the current element, and if not, uses the default country to determine the list of provinces. This should most probably be checking ['#value']['country'] on that element, as ['value']['country'] is not present on this element even where a country has been selected on the form. Patch attached.

I am guessing that this bug may have been introduced at some point since 6.x-3.2 as that version appears to check for ['#value']['country'].

Remaining tasks

Needs testing.