Python: Always log errors before writing diagnostics

So we have the info in the logs if the diagnostics processing fails

Author: RasmusWL

python/extractor/semmle/worker.py

@@ -274,16 +274,16 @@ def _extract_loop(proc_id, queue, trap_dir, archive, options, reply_queue, logge
                     # Syntax errors have already been handled in extractor.py
                     reply_queue.put(("FAILURE", unit, None))
                 except RecursionError as ex:
-                    error = recursion_error_message(ex, unit)
-                    diagnostics_writer.write(error)
                     logger.error("Failed to extract %s: %s", unit, ex)
                     logger.traceback(WARN)
+                    error = recursion_error_message(ex, unit)
+                    diagnostics_writer.write(error)
                     reply_queue.put(("FAILURE", unit, None))
                 except Exception as ex:
-                    error = internal_error_message(ex, unit)
-                    diagnostics_writer.write(error)
                     logger.error("Failed to extract %s: %s", unit, ex)
                     logger.traceback(WARN)
+                    error = internal_error_message(ex, unit)
+                    diagnostics_writer.write(error)
                     reply_queue.put(("FAILURE", unit, None))
                 else:
                     reply_queue.put(("SUCCESS", unit, None))