Remove hard-coded DrawSelectorOnTop on ListFragment's default ListView.

When using the default layout of a ListFragment, the
returned ListView has its DrawSelectorOnTop property
hard-coded to false.
There is no reason for this, as this property is themable.
This change removes the hard-coded attribute.

Change-Id: Idc90fd04680c19d3731b30d84764858a28783864
Signed-off-by: Benoit Lubek <bodlulu@gmail.com>