getDependencyVersion should pin version to the installed version.

[nathanhammond]

getDependencyVersion currently reads package.json to identify which version of a dependency to emit for the generated package.json. It should instead defer to the version that is presently installed in the application as the lockfile may trail the most-recent version, or there may be race conditions with builds and publishing (incredibly unlikely but possible).

ember-cli-fastboot/lib/broccoli/fastboot-config.js

Lines 218 to 224 in 43ffc65

	function getDependencyVersion(pkg, dep) {
	if (!pkg.dependencies) {
	throw new Error(fmt("Could not find FastBoot dependency '%s' in %s/package.json dependencies.", dep, pkg.name));
	}
	return pkg.dependencies[dep];
	}

[nathanhammond]

Closing in favor of #668.