Fix wrong label reference.

static/sfu.html

@@ -122,7 +122,7 @@
                     <input id="presentmike" type="radio" name="presentradio" value="mike"/>
                     <label for="presentmike">microphone</label>
                     <input id="presentboth" type="radio" name="presentradio" value="both"/>
-                    <label for="presentoff">camera and microphone</label>
+                    <label for="presentboth">camera and microphone</label>
                     <div class="clear"></div>
                     <input id="connectbutton" type="submit" class="btn btn-blue" value="Connect"/>
                   </form>