... that contain std::unique_ptr.  With C++11 variadic templates this
apparently works for both std::vector and std::set; associative
containers like std::map have different iterators so need a different
implementation.

Change-Id: I6872445b007875c310d08fa7a8d7311075880b1d
Reviewed-on: https://gerrit.libreoffice.org/19818Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>