fallout from the wide char changes

<sberg> noelgrandin, _rene_, ah, yeah, that's something that broke with 0b07406f
<IZBot> core - Use C++11 char16_t for sal_Unicode - http://cgit.freedesktop.org/libreoffice/core/commit/?id=0b07406f7147b9abbb2095d9e038b13293cb8b10

Change-Id: If4303bd1d8577612250b1857b809b022d13759e4
Reviewed-on: https://gerrit.libreoffice.org/20433Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
Tested-by: Stephan Bergmann <sbergman@redhat.com>