enlightenment: Don't crash if fwin app dialog has no exec_cmd
enlightenment: Don't crash if fwin app dialog has no exec_cmd

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

tizenorg/platform.upstream.enlightenment,tasn/enlightenment,tizenorg/platform.upstream.enlightenment,FlorentRevest/Enlightenment,tizenorg/platform.upstream.enlightenment,FlorentRevest/Enlightenment,tasn/enlightenment,rvandegrift/e,FlorentRevest/Enlightenment,tasn/enlightenment,rvandegrift/e,rvandegrift/e