nimble install error
I am getting the following errors when I run `nimble install nimble`. I am using pre-built binaries instead of installing nim. Any advice on how to fix these errors?

```
$ nimble install nimble --verbose
    Reading official package list
    Prompt: No local packages.json found, download it from internet? [y/N]
y
    Answer: Downloading Official package list
     Trying https://github.com/nim-lang/packages/raw/master/packages.json
   Warning: Downloaded packages.json file is invalid, discarding.
     Trying http://irclogs.nim-lang.org/packages.json
     Trying http://nim-lang.org/nimble/packages.json
     Error: Refresh failed
        ... Downloaded packages.json file is invalid
```