build: Use FAIL_EXIT1 () on failure to exec child [BZ #23990]

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

support/test-container.c

@@ -392,7 +392,7 @@ recursive_remove (char *path)
     /* "rm" would have already printed a suitable error message.  */
     if (! WIFEXITED (status)
 	|| WEXITSTATUS (status) != 0)
-      exit (1);
+      FAIL_EXIT1 ("exec child returned status: %d", status);
 
     break;
   }