Typos in redirect config are fatal / bad messaging

[pushred]

A bad key in the redirect JSON config causes the server to fail in certain environments. Dev seemed to work but deploying to modulus didn't work. Thankfully in the latter I was given better feedback in the log about what was wrong.

https://github.com/SparkartGroupInc/keithurban.net/commit/1ee1fe0ebda4a8d83384b962b973fcc7537d3762

Fatal error: Cannot call method 'charAt' of undefined

vs.

path.js:336
    var isAbsolute = path.charAt(0) === '/',
                          ^
TypeError: Cannot call method 'charAt' of undefined
    at Object.exports.normalize (path.js:336:27)
    at new Redirect (/mnt/data/1/node_modules/solidus/lib/redirect.js:21:33)
    at /mnt/data/1/node_modules/solidus/lib/server.js:142:20
    at fs.js:266:14
    at Object.oncomplete (fs.js:107:15)

[Fauntleroy]

I'm not sure exactly what you want me to do about this. Do you want to check all the keys in the redirect JSON and see if they're on the whitelist? I suppose we could put pre-emptive error checking like that into Solidus, but we'd end up having lots of code in place to respond to weird user input.