FIX issue redefining location in UPDATE only when the name of the location differs

Solving the issue raised at http://stackoverflow.com/questions/24431177/ge-orion-context-broker-when-we-make-an-update-of-the-entity-does-not-allow-us
A little hard to understand all this ...
Can an entity have only ONE attribute with geolocation data?
And that attribute must have a 'special' name - input to the function processContextAttributeVector?