Build: Uses modules version instead of v8.

* Pointed out by @saper via sass#694.
PR URL: sass#743.

Author: am11

lib/extensions.js

@@ -47,11 +47,9 @@ function getBinaryName() {
   } else if (process.env.SASS_BINARY_NAME) {
     binaryName = process.env.SASS_BINARY_NAME;
   } else {
-    var v8SemVersion = process.versions.v8.split('.').slice(0, 3).join('.');
-
     binaryName = [process.platform, '-',
                   process.arch, '-',
-                  v8SemVersion].join('');
+                  process.versions.modules].join('');
   }
 
   return [binaryName, 'binding.node'].join('_');