#656: Fix crashes that caused when using object-rest properties in namespace rule

[preco21]

Fixes #656.

This is the one of long standing issue, where ESLint crashes when you are trying to use object-rest on namespace import:

import * as names from './named-exports';
const {a, b, ...rest} = names; // Cannot read property 'type' of undefined

Also, I have noticed that it's only caused on variable declarations (in the other words, it does not crash on assignment expressions):

import * as names from './named-exports';
let a, b, rest;
({a, b, ...rest} = names); // Nothing happens

I don't know if this is a right solution, but I think it's going to be okay ever since I found that it does not crash when it's not using variable declarations.

I will add notes to changelog and documents once this has confirmed.

[coveralls]

Coverage increased (+0.004%) to 96.234% when pulling 1a084cc on preco21:namespace-crash-fix into 196c238 on benmosher:master.