Auto merge of #3072 - pietroalbini:fix-faq, r=steveklabnik

Remove reference of Rust 1.11.0 release date in the FAQ

In the `--frozen` section of the FAQ, there is a reference to the Rust 1.11.0 release date (probably because it was added in June), which is now in the past. In this pull request I removed that reference, since it's not useful anymore.

I also reflowed the text to 80 chars, to be consistent with the rest of the document :)