my_close: Don't retry on close

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

Even the EINTR case its maybe closed. Take the prudent approach here
an risk leaking one file descriptor rather than closing one that is
nolonger ours.

mysys/my_open.c

@@ -89,10 +89,7 @@ int my_close(File fd, myf MyFlags)
     my_file_info[fd].type= UNOPEN;
   }
 #ifndef _WIN32
-  do
-  {
-    err= close(fd);
-  } while (err == -1 && errno == EINTR);
+  err= close(fd);
 #else
   err= my_win_close(fd);
 #endif