Remove remaining traces of Rand_OpenSSL() from the tree

fe0a0b5 has removed the last use of this routine from pgcrypto, leading
to a useless symbol definition and an extra configure check.

Author: Michael Paquier
Reviewed-by: Daniel Gustafsson, Tom Lane
Discussion: https://postgr.es/m/20190626142544.GN1714@paquier.xyz

configure

@@ -12146,7 +12146,7 @@ done
   # defines OPENSSL_VERSION_NUMBER to claim version 2.0.0, even though it
   # doesn't have these OpenSSL 1.1.0 functions. So check for individual
   # functions.
-  for ac_func in OPENSSL_init_ssl BIO_get_data BIO_meth_new ASN1_STRING_get0_data RAND_OpenSSL
+  for ac_func in OPENSSL_init_ssl BIO_get_data BIO_meth_new ASN1_STRING_get0_data
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"

configure.in

@@ -1212,7 +1212,7 @@ if test "$with_openssl" = yes ; then
   # defines OPENSSL_VERSION_NUMBER to claim version 2.0.0, even though it
   # doesn't have these OpenSSL 1.1.0 functions. So check for individual
   # functions.
-  AC_CHECK_FUNCS([OPENSSL_init_ssl BIO_get_data BIO_meth_new ASN1_STRING_get0_data RAND_OpenSSL])
+  AC_CHECK_FUNCS([OPENSSL_init_ssl BIO_get_data BIO_meth_new ASN1_STRING_get0_data])
   # OpenSSL versions before 1.1.0 required setting callback functions, for
   # thread-safety. In 1.1.0, it's no longer required, and CRYPTO_lock()
   # function was removed.

src/include/pg_config.h.in

@@ -464,9 +464,6 @@
 /* Define to 1 if you have the `random' function. */
 #undef HAVE_RANDOM
 
-/* Define to 1 if you have the `RAND_OpenSSL' function. */
-#undef HAVE_RAND_OPENSSL
-
 /* Define to 1 if you have the <readline.h> header file. */
 #undef HAVE_READLINE_H