Fix var assn

Author: tammy-baylis-swi

instrumentation/opentelemetry-instrumentation-dbapi/src/opentelemetry/instrumentation/dbapi/__init__.py

@@ -301,7 +301,7 @@ def calculate_commenter_data(
             try:
                 db_version = self.connect_module.__version__
             except AttributeError:
-                db_driver = "unknown"
+                db_version = "unknown"
 
         commenter_data = {
             "db_driver": f"{db_driver}:{db_version.split(' ')[0]}",