fix: Override fct_code() to return our fct_code (#129)

This is mandatory according to the documentation, otherwise we have 0
all the time and lose persisted data

include/CSAdapterEqFct.h

@@ -21,7 +21,6 @@ namespace ChimeraTK {
   class CSAdapterEqFct : public EqFct, boost::noncopyable {
    protected:
     boost::shared_ptr<ControlSystemPVManager> controlSystemPVManager_;
-    int fctCode_;
     std::map<std::shared_ptr<ChimeraTK::PropertyDescription>, boost::shared_ptr<D_fct>> doocsProperties_;
     void registerProcessVariablesInDoocs();
     std::vector<ChimeraTK::ProcessVariable::SharedPtr> getProcessVariablesInThisLocation();
@@ -38,6 +37,8 @@ namespace ChimeraTK {
     void init() override;
     void post_init() override;
 
+    int fct_code() override { return code; }
+
     constexpr static int code = 10; // EqFct code
 
     template<class ValueType>