title: error on easy_install cpp-coveralls
body: <p>It happens to me that most of the builds are compiled correctly, but from time to time the same error appears (without changing any .travis.yml parameter)</p>
  
  <p>The error is:</p>
  
  <p><strong>The command "sudo easy_install cpp-coveralls" failed and exited with 1 during .</strong></p>
  
  <p>Now my build got stucked on it when the previous builds have successfully passed this step without problems.</p>
  
  <ul>
  <li><strong>This is the failing build</strong>: <a href="https://travis-ci.org/pubnative/pubnative-ios-library/builds/49482893" rel="nofollow">https://travis-ci.org/pubnative/pubnative-ios-library/builds/49482893</a></li>
  <li><strong>This is the repo</strong>: <a href="https://travis-ci.org/pubnative/pubnative-ios-library/" rel="nofollow">https://travis-ci.org/pubnative/pubnative-ios-library/</a></li>
  </ul>
  
  <p>Why is it so randomly failing?</p>