configdata.pm.in, util/dofile.pl: Make a HERE document stricter.

Fixes #13221
Fixes #12743
Fixes #12078

Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/13225)

configdata.pm.in

@@ -121,7 +121,7 @@ unless (caller) {
         use OpenSSL::fallback '{- sourcefile('external', 'perl', 'MODULES.txt') -}';
         use OpenSSL::Template;
 
-        my $prepend = <<"_____";
+        my $prepend = <<'_____';
 use File::Spec::Functions;
 use lib '{- sourcedir('util', 'perl') -}';
 use lib '{- sourcedir('Configurations') -}';

util/dofile.pl

@@ -71,7 +71,7 @@ sub errorcallback {
 
 my $prepend = <<"_____";
 use File::Spec::Functions;
-use lib "$FindBin::Bin/../Configurations";
+use lib '$FindBin::Bin/../Configurations';
 use lib '$config{builddir}';
 use platform;
 _____