Rework writing crypto/err/openssl.txt

Reading the prologue of this file conserved the "# Function codes"
line, and then duplicated it when rewriting this file, adding a new
"# Function codes" line everytime there's an update.

Better then to skip over all comment lines and have the prologue
defined in mkerr.pl, just the same as we do with the other affected
files.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3664)

util/mkerr.pl

@@ -165,7 +165,6 @@ while ( <IN> ) {
 }
 close IN;
 
-my $statefile_prolog = '';
 if ( ! $statefile ) {
     $statefile = $config;
     $statefile =~ s/.ec/.txt/;
@@ -179,9 +178,7 @@ if ( ! $reindex && $statefile ) {
 
     # Scan function and reason codes and store them: keep a note of the
     # maximum code used.
-    my $collecting = 1;
     while ( <STATE> ) {
-        $statefile_prolog .= $_ if $collecting && ( /^#/ || /^$/ );
         next if /^#/ || /^$/;
         my $name;
         my $code;
@@ -200,7 +197,6 @@ if ( ! $reindex && $statefile ) {
         } else {
             die "Bad line in $statefile:\n$_\n";
         }
-        $collecting = 0;
         my $lib = $name;
         $lib =~ s/_.*//;
         $lib = "SSL" if $lib =~ /TLS/;
@@ -703,8 +699,15 @@ die "Found $errors errors, quitting" if $errors;
 if ( $newstate )  {
     open(OUT, ">$statefile.new")
         || die "Can't write $statefile.new, $!";
-    print OUT $statefile_prolog;
-    print OUT "# Function codes\n";
+    print OUT <<"EOF";
+# Copyright 1999-2017 The OpenSSL Project Authors. All Rights Reserved.
+#
+# Licensed under the OpenSSL license (the "License").  You may not use
+# this file except in compliance with the License.  You can obtain a copy
+# in the file LICENSE in the source distribution or at
+# https://www.openssl.org/source/license.html
+EOF
+    print OUT "\n# Function codes\n";
     foreach my $i ( sort keys %fcodes ) {
         my $short = "$i:$fcodes{$i}:";
         my $t = exists $strings{$i} ? $strings{$i} : "";