DnD: fix callbacks call on many DnD operations.

A leave callback is invoked on the drop target of the previous DnD
operation, leading to inconsistency for applications.
The state of the dropable target was not resetted during drop.
This patch fixes that.

legacy/elementary/src/lib/elm_cnp.c

@@ -1687,6 +1687,7 @@ found:
 
    act = _x11_dnd_action_map(drop->action);
 
+   dropable->last.in = EINA_FALSE;
    if ((!strcmp(dropable->last.type, text_uri)))
      {
         cnp_debug("We found a URI... (%scached) %s\n",