Bug 980102

The original link `$OPENSHIFT_REPO_DIR/../node_modules` is wrong.
The one we need is `$OPENSHIFT_NODEJS_DIR/node_modules`, which
will be used in `build()` if `deplist.txt` is present.

There is another occurrence of `npm install`, but that happens in
`$OPENSHIFT_REPO_DIR`, to which we have write access.

For existing Node.js applications, we simply remove the dangling symlink.

To test, create a Node.js app, then add a module (say `coffee-script`)
to `deplist.txt`, add and commit this change, and push.