Rename the doc/master S3 folder to doc/nightly

[brson]

If the release channel is going to be called nightly we might as well fix this to avoid confusion.

[brson]

cc @alexcrichton @steveklabnik

[brson]

This is currently being managed in nginx rewriting rules, but the s3 folder is called master. I will probably change it sometime in the course of release channel automation upgrades.

[alexcrichton]

This is done.

[alexcrichton]

Ah, but renaming the S3 folder is not.

[steveklabnik]

Seems legit.

[steveklabnik]

Given that http://doc.rust-lang.org/nightly/ resolves, has this been finished?

[alexcrichton]

Not quite just yet, but I've updated the title with the remaining todo item.

[steveklabnik]

What about now?