Title: Using Pre-Signed URLs

Describe the issue:
Previous versions of S3_PING used a file for each node in the cluster which meant that each node in the cluster needed a unique pre-signed URL. Here's an example from the current docs:

http://{s3_bucket_name}.s3.amazonaws.com/node1?AWSAccessKeyId={access_key}\&Expires={expiration_time}\&Signature={signature}

This can now be replaced with a pre-signed URL that points to a single file that is shared between every node in the cluster.

http://{s3_bucket_name}.s3.amazonaws.com/jgroups.list?AWSAccessKeyId={access_key}\&Expires={expiration_time}\&Signature={signature}

Or using an extra folder in the path, like this:

http://{s3_bucket_name}.s3.amazonaws.com/AWS_Cluster/jgroups.list?AWSAccessKeyId={access_key}\&Expires={expiration_time}\&Signature={signature}

It also looks like Example 27.3 is missing a space after the -Djgroups.s3.pre_signed_put_url property and before the -Djgroups.s3.pre_signed_delete_url property.


Suggestions for improvement:


Additional information: