Upload custom image metadata

Upload custom image metadata

This branch automates the use of custom image
metadata at bootstrap and at the same time
solves the issue of bootstrapping against
a private cloud without http access to
cloud storage. 

The bootstrap --source parameter is renamed
--metadata-source and the directory is used
to look for both tools and image metadata.
If image metadata is found, which is the
case after running juju metadata generate-image,
the metadata is uploaded to cloud storage which
automatically adds it to the simplestreams
search path. Previously, the user had to
upload manually.

https://code.launchpad.net/~wallyworld/juju-core/image-metadata-upload/+merge/202565

(do not edit description out of merge proposal)

[wallyworld, 2014-01-21 22:32:00]

Please take a look.

[thumper, 2014-01-22 04:41:51]

LGTM - one suggestion, but not binding.

https://codereview.appspot.com/55300043/diff/1/environs/imagemetadata/upload_...
File environs/imagemetadata/upload_test.go (right):

https://codereview.appspot.com/55300043/diff/1/environs/imagemetadata/upload_...
environs/imagemetadata/upload_test.go:29: func createImageMetadata(c *gc.C)
(string, string, storage.Storage, *imagemetadata.ImageMetadata) {
If you are returning multiple parameters is it often nice to name them so
someone reading the signature can get it without having to look at the return
statements.

[wallyworld, 2014-01-22 04:53:55]

https://codereview.appspot.com/55300043/diff/1/environs/imagemetadata/upload_...
File environs/imagemetadata/upload_test.go (right):

https://codereview.appspot.com/55300043/diff/1/environs/imagemetadata/upload_...
environs/imagemetadata/upload_test.go:29: func createImageMetadata(c *gc.C)
(string, string, storage.Storage, *imagemetadata.ImageMetadata) {
On 2014/01/22 04:41:51, thumper wrote:
> If you are returning multiple parameters is it often nice to name them so
> someone reading the signature can get it without having to look at the return
> statements.

Just for you, done.