= and <> operators have been switched when used on annotations and null values

[Nicklas Nordborg]

1. Create an annotation type for any kind of item
2. Create two items of the specific type. Annotate one of the with 'foo'. Do not annotate the other item.
3. Display the annotation column in the list view and try the following filters: '=' -> Finds the item with an annotation '<>' -> Finds the annotation without an annotation

Clearly the result is switched.

[Nicklas Nordborg]

(In [4693]) Fixes #1206: = and <> operators have been switched when used on annotations and null values