ifcwrap: fix breaking validate_stub (824c1fc)

It's ignoring underscore prefixed functions as not actually used.
Removing underscore to keep it happy without adding new exceptions.

(cherry picked from commit 88c8bd032f)

src/ifcwrap/IfcGeomWrapper.i

@@ -889,11 +889,11 @@ struct ShapeRTTI : public boost::static_visitor<PyObject*>
 	%pythoncode %{
         # Hide the getters with read-only property implementations
         # Keep the owning element alive while its geometry is referenced (#1124).
-        def _geometry_with_backref(self, _f=geometry):
+        def geometry_with_backref(self, _f=geometry):
             result = _f(self)
             result._parent = self
             return result
-        geometry = property(_geometry_with_backref)
+        geometry = property(geometry_with_backref)
 	%}
 };
 
@@ -901,11 +901,11 @@ struct ShapeRTTI : public boost::static_visitor<PyObject*>
 	%pythoncode %{
         # Hide the getters with read-only property implementations
         # Keep the owning element alive while its geometry is referenced (#1124).
-        def _geometry_with_backref(self, _f=geometry):
+        def geometry_with_backref(self, _f=geometry):
             result = _f(self)
             result._parent = self
             return result
-        geometry = property(_geometry_with_backref)
+        geometry = property(geometry_with_backref)
 	%}
 };
 
@@ -931,11 +931,11 @@ struct ShapeRTTI : public boost::static_visitor<PyObject*>
     %pythoncode %{
         # Hide the getters with read-only property implementations
         # Keep the owning element alive while its geometry is referenced (#1124).
-        def _geometry_with_backref(self, _f=geometry):
+        def geometry_with_backref(self, _f=geometry):
             result = _f(self)
             result._parent = self
             return result
-        geometry = property(_geometry_with_backref)
+        geometry = property(geometry_with_backref)
         volume = property(calc_volume_)
         surface_area = property(calc_surface_area_)
     %}