Added valid values to the configuration examples

Signed-off-by: Shreyas Karnik <karnik.shreyas@gmail.com>

doc/configuration.md

@@ -20,6 +20,7 @@ storage:
 		encrypt: true
 		secure: true
 		v4auth: true
+		chunksize: 5242880
 		rootdirectory: /s3/object/name/prefix
 auth:
 	silly:
@@ -117,6 +118,7 @@ storage:
 		encrypt: true
 		secure: true
 		v4auth: true
+		chunksize: 5242880
 		rootdirectory: /s3/object/name/prefix
 ```