markup std::unique_ptr where coverity warns a dtor might throw exceptions which
won't throw in practice, or where std::terminate is an acceptable response if
they do

Change-Id: Icc99cdecf8d8b011e599574f0a05b59efd1c65c2
Reviewed-on: https://gerrit.libreoffice.org/41561Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>