Entity ref and decl was disabled since 2014, let's remove it now.

Change-Id: I35dac78b8530bab99e955bf68dfe3f8951a63f99
Reviewed-on: https://gerrit.libreoffice.org/40998Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Tested-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>