Filip Roséen authored Jul 24, 2016 and François Cartegnie committed Jul 24, 2016

This commit fixes the below:

 - Since we are dealing with the playlist, it should be locked for the
   operations inside PLModel::getPLRootType.

 - There is a problem associated with comparing the value of the
   different node's p_input (input_item_t*).

   Given that the input_item_t* can be shared across several nodes, we
   could end up in a state where the prior implementation leads to a
   false-positive.

Signed-off-by: Francois Cartegnie <fcvlcdev@free.fr>