Device picker: add title to fix offset in progressbar

 * Add a title to device picker fragment in order to
   move the progressbar to the correct place

Test: make Settings, share a file via Bluetooth,
verify progressbar is properly placed

Change-Id: I2fcf293ed2d70d123d65cf76051a6d7d745a773b
Signed-off-by: Timi Rautamäki <timi.rautamaki@gmail.com>