Don't retry on close

According to close(2) "Retrying the close() after a failure return is
the wrong thing to do"

Corrects 5c81cb88 in MDEV-15635

mysys/my_fopen.c

@@ -171,10 +171,7 @@ int my_fclose(FILE *fd, myf MyFlags)
     my_file_info[file].type= UNOPEN;
   }
 #ifndef _WIN32
-  do
-  {
   err= fclose(fd);
-  } while (err == -1 && errno == EINTR);
 #else
   err= my_win_fclose(fd);
 #endif