Catching dropped JSON exceptions. [finishing #58740354]

@bryceallison @jfouse I anticipate this will fix the Travis-CI failure, but it smells a bit.

MultiJSON is an intridea gem that tries to decouple gems from a particular JSON parser so people are free to choose their own. Problem is, depending on the environment, it can fail to recast parse failures to MultiJson::LoadError(s).

I remedied this by treating any exception in the GET as a JSON error. But I think that's too broad. Ideas?