Remove non needed code for HeaderAdapter

- before, we were showing a Swich for WiFi and Bluetooth entries
in the Headers. As this is no more the case, remove the code
that is no more usefull.

- as a side effect, we are also removing the call to update the
Search Index that was running when the Settings app was resuming
or pausing.

Change-Id: I26b40df5c7a664d196a249840638d89909b6bc24