Fix warning from Ruby master (will be 3.2.0) (#2785)

Fix: warning: undefining the allocator of T_DATA class Puma::MiniSSL::Engine
test_puma_server_ssl.rb - Fix warning: assigned but unused variable

ext/puma_http11/mini_ssl.c

@@ -608,7 +608,10 @@ void Init_mini_ssl(VALUE puma) {
   ERR_load_crypto_strings();
 
   mod = rb_define_module_under(puma, "MiniSSL");
+
   eng = rb_define_class_under(mod, "Engine", rb_cObject);
+  rb_undef_alloc_func(eng);
+
   sslctx = rb_define_class_under(mod, "SSLContext", rb_cObject);
   rb_define_alloc_func(sslctx, sslctx_alloc);
   rb_define_method(sslctx, "initialize", sslctx_initialize, 1);

test/test_puma_server_ssl.rb

@@ -349,7 +349,6 @@ class TestPumaServerSSLWithCertPemAndKeyPem < Minitest::Test
     events = SSLEventsHelper.new STDOUT, STDERR
     server = Puma::Server.new app, events
     server.add_ssl_listener host, port, ctx
-    host_addrs = server.binder.ios.map { |io| io.to_io.addr[2] }
     server.run
 
     http = Net::HTTP.new host, server.connected_ports[0]