We now set up a .djblets symlink in order to have easy access to

Djblets's package.json for dependency management. Unfortunately, we

were setting this up after calling npm install, meaning we weren't

installing any of those dependencies.
This change moves that logic to set up .djblets before we install

those dependencies.

Removed .djblets and node_modules and re-ran setup.py develop.

Checked node_modules for all the required dependencies.