title: Ignore "Local NPM module not found" warning in Grunt
body: <p>I'm using <strong>matchdep</strong> to read dependencies from my <code>package.json</code> file into <code>grunt</code>.</p>
  
  <pre><code>require('matchdep').filterAll('grunt-*').forEach(grunt.loadNpmTasks);
  </code></pre>
  
  <p>I have my dependencies split between <code>dependencies</code> (for everyone) and <code>devDependencies</code> (for front-end developers.) </p>
  
  <p>Our back-end devs will run the following to get a build of the static assets without requiring jasmine, phantomJS, etc (things that will be run by front-end devs and the CI server)</p>
  
  <pre><code>$ npm install --production
  $ grunt build
  </code></pre>
  
  <p>However, when using the <code>--production</code> build, <code>grunt.loadNpmTasks()</code> will emit a warning for any missing packages. </p>
  
  <pre><code>&gt;&gt; Local Npm module "grunt-contrib-watch" not found. Is it installed?
  </code></pre>
  
  <p><strong>Is there a way to supress this warning?</strong></p>