plugin-remove-trailing-slashes clashes with dev-404-page

[ahmadnassri]

Description

When using the gatsby-plugin-remove-trailing-slashes plugin, the dev-404-page throws in an error:

TypeError: Cannot read property 'componentChunkName' of undefined

this can be traced back here:

gatsby/packages/gatsby/cache-dir/root.js

Lines 177 to 188 in 97f4cb1

	const dev404Page = pages.find(p => p.path === `/dev-404-page/`)
	return createElement(Route, {
	key: `404-page`,
	component: props =>
	createElement(
	syncRequires.components[dev404Page.componentChunkName],
	{
	...props,
	...syncRequires.json[dev404Page.jsonName],
	}
	),
	})

Environment

Gatsby version: 1.1.28
Node.js version: 9.4.0
Operating System: Linux

File contents (if changed):

gatsby-config.js:

plugins: ['gatsby-plugin-remove-trailing-slashes']

Actual result

dev-404-page throws a TypeError exception

Expected behavior

should see dev mode 404 page

Steps to reproduce

1. add gatsby-plugin-remove-trailing-slashes to plugins

2. attempt to load a no match route

[ahmadnassri]

I have a PR incoming with potential fix.