Heads up: tools-url name change; image metadata change

[Ian Booth]

Hi

For those folks running juju from source, if you are using the tools-url config
attribute to point to a custom tools location, or are using custom image
metadata, read on. Some changes have been committed to trunk. These changes will
be packaged with the next release.

To get some consistency between image and tools simplestreams configuration, the
"tools-url" config attribute has been renamed to "tools-metadata-url".

So now we have
- tools-metadata-url (was tools-url)
- image-metadata-url

In addition, another change in trunk is the cloud storage (aka control bucket)
directory where custom image metadata is stored. Currently, the image metadata
is put in a streams/v1 directory in the root of the control bucket. Now, there
is expected to be an "images" folder which contains the streams metadata.

The above change means that now, in the cloud storage (private bucket), there's
optionally a "tools" folder for simplestreams tools metadata and an "images"
folder for simplestreams images metadata. If you have existing image metadata,
simply create a new top level "images" folder and move the streams directory to
that location.

The "juju metadata generate-image" command is also updated to reflect the above
change. It will put all generated metadata under an "images" folder in the
nominated local destination directory. So then in the case of swift for example,
you just go "swift upload control-bucket-name images/streams/v1/*" and the
metadata will be put in the right place.