C: fixed a bug when opening or creating a new column directory where the

DMS was not saved in the struct

src/obidmscolumndir.c

@@ -175,6 +175,7 @@ OBIDMS_column_directory_p obi_open_column_directory(OBIDMS_p dms, const char* co
 	}
 
 	// Initialize the data structure
+	column_directory->dms = dms;
 	strcpy(column_directory->directory_name, column_directory_name);
 	strcpy(column_directory->column_name, column_name);