CoreAudio: Mismatched new[]/delete in several places.

The CoreAudio plugin code in QtMultimedia had several different places
where an array was allocated with "new[]" and deleted with "delete".
Fixed by deleting with "delete[]".

Task-number: QTBUG-37861
Change-Id: Id85bc07a054ad161b0403cc0fe5c56ec5b41d4e3
Reviewed-by: Andy Nichols <andy.nichols@digia.com>