Small fixes to include/

Small fixes to include/

* Function bt_component_filter_borrow_from_self is declared, but does not
  actually exist.

* Parameters to bt_self_component_{get,set}_data are named "private",
  which is the old naming scheme.  Change that to self.

* bt_component_graph is typedef'ed to struct bt_component_graph, which
  doesn't actually exist.  struct bt_graph exists, and there's already a
  typedef for it.