...after 27463197 "clang-tidy bugprone-copy-
constructor-init" made e.g. the SfxStyleSheetBase copy ctor (in
svl/source/items/style.cxx) use the copy instead of the default ctor for its
OWeakTypeObject sub-object

Change-Id: I7deec4ea2f968587ba1dc03e33206cecfa3f8df5
Reviewed-on: https://gerrit.libreoffice.org/60644
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>