coverity#707771 coverity gold, Uninitialized m_refCount

Change-Id: I98398a3cd7a86a5f31c711f7f1cff0d467a1d2e5
(cherry picked from commit eb07ab05c3b8774ab2b2059befef0eadf61c97d6)
Reviewed-on: https://gerrit.libreoffice.org/7901
Reviewed-by: Fridrich Strba <fridrich@documentfoundation.org>
Tested-by: Fridrich Strba <fridrich@documentfoundation.org>