elc_fileselector.c: check null path before fileselector populate.
elc_fileselector.c: check null path before fileselector populate.

If no path was selected we don't need to populate fileselector.
This fixes https://phab.enlightenment.org/T132.
Thanks uartie for the report.

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