Title: Building Object Storage Service Ring Files

Describe the issue:
The documentation does not produce a working swift installation if one does not specify exactly the right name for object_builder_file, container_builder_file and account_builder_file.

First, it's hard to see that this is in italic and should be replaced by something, so I used these exact names, that resulted in the following files:

[root@localhost swift(keystone_admin)]# ls /etc/swift/*builder*
/etc/swift/account_builder_file  /etc/swift/account_builder_file.ring.gz  /etc/swift/container_builder_file  /etc/swift/container_builder_file.ring.gz  /etc/swift/object_builder_file  /etc/swift/object_builder_file.ring.gz

These are not the default filenames for swift, and it is not mentioned anywhere that if you use a custom name for these, then where to set swift to use them.

As a result, openstack-swift-proxy does not start up, because it does not find the ring files (from /var/log/swift-startup.log):

IOError: [Errno 2] No such file or directory: '/etc/swift/object.ring.gz'

Suggestions for improvement:

Use the "account.builder", "container.builder", "object.builder" file names in the documentation, without italic, because you're not providing a way to customize their names anyway.

# ls /etc/swift/*gz 
/etc/swift/account.ring.gz  /etc/swift/container.ring.gz  /etc/swift/object.ring.gz

Additional information:

Related issue at the same page:

At the output of the ls command for checking for the files, the example files are missing the ".ring" part, that will be automatically put there by the ring-builder.

Suggestion: Change the sample output of the ls command below to a correct one. With the recommended changes it would look like this:

$ ls /etc/swift/*gz 
/etc/swift/account.ring.gz  /etc/swift/container.ring.gz  /etc/swift/object.ring.gz