aglio-theme-olio@1.6.3 Failed to exec postinstall script

It fails with both `aglio` `2.2.0` and `2.2.1`. This happened after the `aglio-theme-olio` has been upgraded to `1.6.3`.

``` bash
npm ERR! Linux 4.0.9-boot2docker
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "i" "aglio"
npm ERR! node v4.4.3
npm ERR! npm v2.15.1
npm ERR! code ELIFECYCLE

npm ERR! aglio-theme-olio@1.6.3 postinstall: `node scripts/setup-cache.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the aglio-theme-olio@1.6.3 postinstall script 'node scripts/setup-cache.js'.
npm ERR! This is most likely a problem with the aglio-theme-olio package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! node scripts/setup-cache.js
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs aglio-theme-olio
npm ERR! Or if that isn't available, you can get their info via:
npm ERR!
npm ERR! npm owner ls aglio-theme-olio
npm ERR! There is likely additional logging output above.
npm info preuninstall aglio-theme-olio@1.6.3
npm info uninstall aglio-theme-olio@1.6.3
npm info postuninstall aglio-theme-olio@1.6.3
npm info preuninstall aglio@2.2.0
npm info uninstall aglio@2.2.0
npm info postuninstall aglio@2.2.0

npm ERR! Please include the following file with any support request:
npm ERR! /webapp/npm-debug.log
```

`npm-debug.log` says:

```
20393 info aglio-theme-olio@1.6.3 Failed to exec postinstall script
20394 verbose unsafe-perm in lifecycle false
20395 verbose unlock done using /root/.npm/_locks/aglio-theme-olio-a96b3bff19dc352e.lock for /webapp/node_modules/aglio/node_modules/aglio-theme-olio
20396 info postinstall protagonist@1.3.3
20397 verbose unlock done using /root/.npm/_locks/protagonist-cb036dc5e581a117.lock for /webapp/node_modules/aglio/node_modules/protagonist
20398 verbose about to build /webapp/node_modules/aglio
20399 verbose unlock done using /root/.npm/_locks/aglio-a3c3fc6176a22ff3.lock for /webapp/node_modules/aglio
20400 verbose stack Error: aglio-theme-olio@1.6.3 postinstall: `node scripts/setup-cache.js`
20400 verbose stack Exit status 1
20400 verbose stack at EventEmitter. (/usr/local/lib/node_modules/npm/lib/utils/lifecycle.js:217:16)
20400 verbose stack at emitTwo (events.js:87:13)
20400 verbose stack at EventEmitter.emit (events.js:172:7)
20400 verbose stack at ChildProcess. (/usr/local/lib/node_modules/npm/lib/utils/spawn.js:24:14)
20400 verbose stack at emitTwo (events.js:87:13)
20400 verbose stack at ChildProcess.emit (events.js:172:7)
20400 verbose stack at maybeClose (internal/child_process.js:827:16)
20400 verbose stack at Process.ChildProcess._handle.onexit (internal/child_process.js:211:5)
20401 verbose pkgid aglio-theme-olio@1.6.3
20402 verbose cwd /webapp
20403 error Linux 4.0.9-boot2docker
20404 error argv "/usr/local/bin/node" "/usr/local/bin/npm" "i" "aglio"
20405 error node v4.4.3
20406 error npm v2.15.1
20407 error code ELIFECYCLE
20408 error aglio-theme-olio@1.6.3 postinstall: `node scripts/setup-cache.js`
20408 error Exit status 1
20409 error Failed at the aglio-theme-olio@1.6.3 postinstall script 'node scripts/setup-cache.js'.
20409 error This is most likely a problem with the aglio-theme-olio package,
20409 error not with npm itself.
20409 error Tell the author that this fails on your system:
20409 error node scripts/setup-cache.js
20409 error You can get information on how to open an issue for this project with:
20409 error npm bugs aglio-theme-olio
20409 error Or if that isn't available, you can get their info via:
20409 error
20409 error npm owner ls aglio-theme-olio
20409 error There is likely additional logging output above.
20410 verbose exit [ 1, true ]
```

Reproduce the failure with npm install aglio using the Node and npm versions reported in the issue. Start with aglio-theme-olio@1.6.3's scripts/setup-cache.js and its postinstall invocation, then inspect the npm debug output for the underlying error. Done means the package installs successfully without the postinstall script exiting nonzero.

Written by the indexing model from the issue text.