Since HEADER_DES_H has been the protector of des.h since libdes

(before SSLeay, maybe?), it's better to have that macro protect
the compatibility header des_old.h.  In the new des.h, let's use
a slightly different protecting macro.

The rationale is that there are application that might include (via
other header files, perhaps) both an old libdes des.h and OpenSSL's
des.h.  Whichever comes first would overshadow the other because of
the clash in protecting macro.  This fix solves that problem.

crypto/des/des.h

@@ -56,8 +56,8 @@
  * [including the GNU Public Licence.]
  */
 
-#ifndef HEADER_DES_H
-#define HEADER_DES_H
+#ifndef HEADER_NEW_DES_H
+#define HEADER_NEW_DES_H
 
 #ifdef OPENSSL_NO_DES
 #error DES is disabled.

crypto/des/des_old.h

@@ -88,8 +88,8 @@
  *
  */
 
-#ifndef HEADER_DES_OLD_H
-#define HEADER_DES_OLD_H
+#ifndef HEADER_DES_H
+#define HEADER_DES_H
 
 #ifdef OPENSSL_NO_DES
 #error DES is disabled.