Fix a crash when an app requests Bluetooth to be discoverable

* When an app requests Bluetooth to be discoverable with a timeout and a
  non null EXTRA_PACKAGE_NAME, Settings app should put in the correct
  timeout values in the dialog string

Bug: 36870303
Test: make, try making Bluetooth discoverable via
      ACTION_REQUEST_DISCOVERABLE intent

Change-Id: I0cebc2f20371c9de5f28feb26425422c0777aa45