More queryInterface related cleanup.

Change-Id: I97d064c425389e687c6f0fbc3a962080f46dd511
Reviewed-on: https://gerrit.libreoffice.org/3568Reviewed-by: Fridrich Strba <fridrich@documentfoundation.org>
Tested-by: Fridrich Strba <fridrich@documentfoundation.org>