ecore: Fix warning about err_no

Double warning, yay:
 explicitly assigning value of variable of type 'int' to itself
 variable 'err_no' is uninitialized when used here

See 1abbfdd1f7

src/lib/ecore/ecore_main.c

@@ -1766,7 +1766,7 @@ _ecore_main_select(double timeout)
 
    eina_evlog("!SLEEP", NULL, 0.0, t ? "timeout" : "forever");
    ret = main_loop_select(max_fd + 1, &rfds, &wfds, &exfds, t);
-   err_no = err_no;
+   err_no = errno;
    eina_evlog("!WAKE", NULL, 0.0, NULL);
 
    _ecore_time_loop_time = ecore_time_get();