eo_cxx: Fix leakage of eo objects by removing unnecessary "eo_ref"

Removed the call to eo_ref in the conversion from eo::base to the native
Eo* (in "to_c" function) in order to avoid eo objects being leaked.

src/bindings/eo_cxx/eo_cxx_interop.hh

@@ -16,7 +16,7 @@ namespace efl { namespace eolian {
 inline Eo*
 to_c(efl::eo::base const& x)
 {
-   return ::eo_ref(x._eo_ptr());
+   return x._eo_ptr();
 }
 
 inline const char*