fix: Use logging level info when file_cache is not available (#1125)

googleapiclient/discovery_cache/__init__.py

diff --git a/googleapiclient/discovery_cache/__init__.py b/googleapiclient/discovery_cache/__init__.py
index 455ff62..197f6bc 100644
--- a/googleapiclient/discovery_cache/__init__.py
+++ b/googleapiclient/discovery_cache/__init__.py
@@ -44,6 +44,7 @@
         from . import file_cache
 
         return file_cache.cache
-    except Exception as e:
-        LOGGER.warning(e, exc_info=True)
+    except Exception:
+        LOGGER.info("file_cache is only supported with oauth2client<4.0.0",
+            exc_info=False)
         return None