When symlinking the Ink tree for development, I began to hit a confusing

issue with Spina class setup. It turns out that we were getting two

copies of Spina, two copies of Backbone, and two copies of Underscore in

our 3rdparty.js build.
The reason for this is that the Ink tree had its own node_modules, and

Rollup prioritized pulling Ink's dependencies from there. That gave us

unique copies for Ink that were namespaced internally separately from

Review Board's. That also meant that Spina state was then kept in two

places, causing all manner of problems.
The reason this was happening was that Rollup.js defaults to considering

any and all node_modules paths, by way of the moduleDirectories

setting. This differs from modulePaths, which is an explicit set of

paths (absolute or relative to the source tree).
Since we know we only want the top-level one, we can set

moduleDirectories to an empty list, ensuring that nested

node_modules are no longer considered when bundling.

Verified that this solved my duplicate module issue.