elementary: Fix issue with event data causing an invalid free
elementary: Fix issue with event data causing an invalid free

Summary: Since we end up calling free on the event->data parameter
after a drop is completed, we should actually be allocating a string
for this data (to be free'd later). This also fixes an issue where the
event length was not being set.

@fix

Signed-off-by: Chris Michael <177aeddb9e34930a357ecd8dd2d21c80fe280c85@samsung.com>

FlorentRevest/Elementary,tasn/elementary,FlorentRevest/Elementary,tasn/elementary,tasn/elementary,tasn/elementary,rvandegrift/elementary,tasn/elementary,rvandegrift/elementary,rvandegrift/elementary,FlorentRevest/Elementary,rvandegrift/elementary,FlorentRevest/Elementary