Report error to user for problems loading node-sass

[acouch]

This addresses #561

This provides the full error instead of:

sass-loader` requires `node-sass` >=4. Please install a compatible version..

When I had the wrong node-sass binding for my version of Linux I get the following with this PR:

Module build failed: Error: Missing binding /node_modules/node-sass/vendor/linux-x64-51/binding.node
Node Sass could not find a binding for your current environment: Linux 64-bit with Node.js 7.x

Which directed me to the actual problem.

[jsf-clabot]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #562 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #562   +/-   ##
=======================================
  Coverage   97.58%   97.58%           
=======================================
  Files           6        6           
  Lines         124      124           
=======================================
  Hits          121      121           
  Misses          3        3

Impacted Files	Coverage Δ
lib/loader.js	100% <ø> (ø)	⬆️

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[alexander-akait]

/cc @jhnns

[jhnns]

Awesome 👍 this makes totally sense and sorry for hiding the original error.

[svewag]

When will this change be released?

[alexander-akait]

in 7 version

[svewag]

In v7.0.1 it is not fixed:
https://github.com/webpack-contrib/sass-loader/blob/v7.0.1/lib/loader.js#L32