Devserver: remove the Known Issues. They're empty and it was a silly idea to

chrome/common/extensions/docs/templates/articles/app_hardware.html

 <h1>Accessing Hardware Devices</h1>
 
 <p>
 This doc shows you how packaged apps can connect to USB devices
 and read from and write to a user's serial ports.
 See also the reference docs for the
 <a href="usb.html">USB API</a>
 and the
 <a href="serial.html">Serial API</a>.
-The <a href="bluetooth.html">Bluetooth API</a> is also available
-(<a href="app_known_issues.html">known issues</a> still to be resolved);
+The <a href="bluetooth.html">Bluetooth API</a> is also available;
 we've include a link to a Bluetooth sample below.
 </p>
 
 <p class="note">
 <b>API Samples: </b>
 Want to play with the code?
 Check out the
 <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/serial">serial</a>,
 <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/servo">servo</a>,
 <a href="https://github.com/GoogleChrome/chrome-app-samples/tree/master/usb">usb</a>,
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 <p>
 You can flush your serial port buffer by issuing the flush command:
 </p>
 
 <pre>
   chrome.serial.flush(connectionId, onFlush);
 </pre>
 
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