Logging: Defensively access provider resource

Fixes open-telemetry#810

Author: owais

Diff for: instrumentation/opentelemetry-instrumentation-logging/src/opentelemetry/instrumentation/logging/__init__.py

@@ -78,7 +78,7 @@ def instrumentation_dependencies(self) -> Collection[str]:
     def _instrument(self, **kwargs):
         service_name = ""
         provider = kwargs.get("tracer_provider", None) or get_tracer_provider()
-        resource = provider.resource if provider else None
+        resource = getattr(provider, "resource", None)
         if resource:
             service_name = resource.attributes.get("service.name")