config: remove all defines of HAVE_DES_H

As there's no code using it.

Closes #5144
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e412b05..e70a6e3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -798,7 +798,6 @@
 check_include_file_concat("arpa/tftp.h"      HAVE_ARPA_TFTP_H)
 check_include_file_concat("assert.h"         HAVE_ASSERT_H)
 check_include_file_concat("crypto.h"         HAVE_CRYPTO_H)
-check_include_file_concat("des.h"            HAVE_DES_H)
 check_include_file_concat("err.h"            HAVE_ERR_H)
 check_include_file_concat("errno.h"          HAVE_ERRNO_H)
 check_include_file_concat("fcntl.h"          HAVE_FCNTL_H)
diff --git a/lib/config-os400.h b/lib/config-os400.h
index a302828..7beb81f 100644
--- a/lib/config-os400.h
+++ b/lib/config-os400.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -97,9 +97,6 @@
 /* Define if you have the <crypto.h> header file. */
 #undef HAVE_CRYPTO_H
 
-/* Define if you have the <des.h> header file. */
-#undef HAVE_DES_H
-
 /* Define if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H
 
diff --git a/lib/config-riscos.h b/lib/config-riscos.h
index 4af9498..0ddf487 100644
--- a/lib/config-riscos.h
+++ b/lib/config-riscos.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -98,9 +98,6 @@
 /* Define if you have the <crypto.h> header file. */
 #undef HAVE_CRYPTO_H
 
-/* Define if you have the <des.h> header file. */
-#undef HAVE_DES_H
-
 /* Define if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H
 
diff --git a/lib/config-symbian.h b/lib/config-symbian.h
index 82a27bf..7f17dce 100644
--- a/lib/config-symbian.h
+++ b/lib/config-symbian.h
@@ -122,9 +122,6 @@
 /* Define to 1 if you have the <crypto.h> header file. */
 /* #undef HAVE_CRYPTO_H */
 
-/* Define to 1 if you have the <des.h> header file. */
-/* #undef HAVE_DES_H */
-
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #define HAVE_DLFCN_H 1
 
diff --git a/lib/config-tpf.h b/lib/config-tpf.h
index a79afae..199dfbc 100644
--- a/lib/config-tpf.h
+++ b/lib/config-tpf.h
@@ -115,10 +115,6 @@
 /* #undef HAVE_CRYPTO_H */
 #define HAVE_CRYPTO_H 1
 
-/* Define to 1 if you have the <des.h> header file. */
-/* #undef HAVE_DES_H */
-#define HAVE_DES_H 1
-
 /* Define to 1 if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H 1
 
diff --git a/lib/config-vxworks.h b/lib/config-vxworks.h
index 2769cdf..14bf0be 100644
--- a/lib/config-vxworks.h
+++ b/lib/config-vxworks.h
@@ -137,9 +137,6 @@
 /* Define to 1 if you have the <crypto.h> header file. */
 /* #undef HAVE_CRYPTO_H */
 
-/* Define to 1 if you have the <des.h> header file. */
-/* #undef HAVE_DES_H */
-
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #define HAVE_DLFCN_H 1
 
diff --git a/lib/curl_config.h.cmake b/lib/curl_config.h.cmake
index 6c01096..24b693e 100644
--- a/lib/curl_config.h.cmake
+++ b/lib/curl_config.h.cmake
@@ -166,9 +166,6 @@
 /* Define to 1 if you have the <crypto.h> header file. */
 #cmakedefine HAVE_CRYPTO_H 1
 
-/* Define to 1 if you have the <des.h> header file. */
-#cmakedefine HAVE_DES_H 1
-
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #cmakedefine HAVE_DLFCN_H 1