cppcheck: Return value of std::remove() ignored. Elements remain in container.

Change-Id: I1e3bcb013d27c6f9a1484c9f1e23b63f42615b9b
Reviewed-on: https://gerrit.libreoffice.org/12460
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>