connection: remove redundant assignment

the code is something like:

  if (object == NULL && ...) {
      object = NULL;
      return;
  }

first, the object is already NULL, second, the assignment has no effect
since we return from the function right away

Signed-off-by: Marek Chalupa <mchqwerty@gmail.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Jonas Ådahl <jadahl@gmail.com>