title: Publishing fails after unpublishing
body: <p>In my application I do the following steps:</p>
  
  <ol>
  <li>Publish audio only</li>
  <li>Unpublish</li>
  <li>Publish audio+video</li>
  <li>Unpublish</li>
  <li>Publish audio only</li>
  </ol>
  
  <p>At stage 5 it fails with the following error:</p>
  
  <blockquote>
    <p>index.js:460 OT.Publisher.onPublishingTimeoutonPublishingTimeout @
    index.js:460(anonymous function) @ index.js:1472 index.js:332
    OT.Publisher State Change Failed: 'Failed' cannot transition to
    'MediaBound'stateChangeFailed @ index.js:332signalChangeFailed @
    generate_simple_state_machine.js:38handleInvalidStateChanges @
    generate_simple_state_machine.js:55set @
    generate_simple_state_machine.js:65onPublishingTimeout @
    index.js:477(anonymous function) @ index.js:1472 ot_error.js:341
    OT.exception :: title: Unable to Publish (1500) msg:
    ICEWorkflow_exceptionHandler @
    ot_error.js:341OTError.handleJsException @
    ot_error.js:412onPublishingTimeout @ index.js:493(anonymous function)
    @ index.js:1472 handle.js:1071 1500 "Session.publish :: Could not
    publish in a reasonable amount of time"</p>
  </blockquote>
  
  <p>I could reproduce this in all devices that were accessible  to me at that time:</p>
  
  <ul>
  <li>Chrome on iMac</li>
  <li>Firefox on iMac</li>
  <li>Chrome on Macbook pro</li>
  <li>Chrome on</li>
  <li>Android 4.x</li>
  </ul>