MDEV-20170 main.tls_version and main.tls_version1 fail in buildbot on RHEL8

Instead of trying to detect MinProtocol=TLSv1.2 in all possible
sections of files in all possible locations where openssl is configured
to find its configuration in all possible distros (and these locations
are mutually different in Debian, Ubuntu, and RHEL, btw) - just make
mtr to instruct openssl not to read any config files at all.

mysql-test/mysql-test-run.pl

@@ -2424,8 +2424,10 @@ sub environment_setup {
   #
   $ENV{'LC_ALL'}=             "C";
   $ENV{'LC_CTYPE'}=           "C";
-
   $ENV{'LC_COLLATE'}=         "C";
+
+  $ENV{'OPENSSL_CONF'}=       "/dev/null";
+
   $ENV{'USE_RUNNING_SERVER'}= using_extern();
   $ENV{'MYSQL_TEST_DIR'}=     $glob_mysql_test_dir;
   $ENV{'DEFAULT_MASTER_PORT'}= $mysqld_variables{'port'};

mysql-test/suite.pm

@@ -89,16 +89,6 @@ sub skip_combinations {
   $skip{'main/ssl_verify_ip.test'} = 'x509v3 support required'
     unless $openssl_ver ge "1.0.2";
 
-  my $openssl_cnf='/etc/ssl/openssl.cnf';
-  if ($openssl_ver and open my $f, '<', $openssl_cnf) {
-    local $/;
-    my $cnf=<$f>;
-    $skip{'main/tls_version.test'} = "TLSv1.1 disabled in $openssl_cnf"
-      if $cnf =~ /^\s*MinProtocol\s*=\s*TLSv1.[2-9]/m;
-    $skip{'main/tls_version1.test'} = "TLSv1.0 disabled in $openssl_cnf"
-      if $cnf =~ /^\s*MinProtocol\s*=\s*TLSv1.[1-9]/m;
-  }
-
   %skip;
 }