lib: fix module linter issues by setting root

Eslint searches parent directories looking for config files until it
finds one with "root: true" in it. This sets "root: true" in CitGM's
tmpDir to avoid that.

Fixes: nodejs#399

lib/temp-directory.js

@@ -5,6 +5,7 @@ const mkdirp = require('mkdirp');
 const osenv = require('osenv');
 const rimraf = require('rimraf');
 const uuid = require('uuid');
+const fs = require('fs');
 
 function create(context, next) {
   if (context.options && context.options.tmpDir) {
@@ -21,7 +22,17 @@ function create(context, next) {
     if (err) {
       return next(err);
     }
-    return next(null, context);
+    /* Tells eslint running in module tests not to look for config files above
+       this temp directory. */
+    const eslintrcPath = path.join(context.path, '.eslintrc.yml');
+    context.emit('data', 'verbose', context.module.name + ' mk.eslintrc',
+        eslintrcPath);
+    fs.writeFile(eslintrcPath, 'root: true', function (err) {
+      if (err) {
+        return next(err);
+      }
+      return next(null, context);
+    });
   });
 }