Feature detect to make net/http usable with JRuby

Handle missing session_new_cb= and do not call
session_cache_mode=, as JRuby SSL does not support
these methods.

lib/net/http.rb

@@ -1051,10 +1051,14 @@ def connect
           end
         end
         @ssl_context.set_params(ssl_parameters)
-        @ssl_context.session_cache_mode =
-          OpenSSL::SSL::SSLContext::SESSION_CACHE_CLIENT |
-          OpenSSL::SSL::SSLContext::SESSION_CACHE_NO_INTERNAL_STORE
-        @ssl_context.session_new_cb = proc {|sock, sess| @ssl_session = sess }
+        unless @ssl_context.session_cache_mode.nil? # a dummy method on JRuby
+          @ssl_context.session_cache_mode =
+              OpenSSL::SSL::SSLContext::SESSION_CACHE_CLIENT |
+                  OpenSSL::SSL::SSLContext::SESSION_CACHE_NO_INTERNAL_STORE
+        end
+        if @ssl_context.respond_to?(:session_new_cb) # not implemented under JRuby
+          @ssl_context.session_new_cb = proc {|sock, sess| @ssl_session = sess }
+        end
 
         # Still do the post_connection_check below even if connecting
         # to IP address

test/net/http/test_https.rb

@@ -152,12 +152,14 @@ def test_session_reuse
     end
 
     http.start
-    assert_equal false, http.instance_variable_get(:@socket).io.session_reused?
+    session_reused = http.instance_variable_get(:@socket).io.session_reused?
+    assert_false session_reused unless session_reused.nil? # can not detect re-use under JRuby
     http.get("/")
     http.finish
 
     http.start
-    assert_equal true, http.instance_variable_get(:@socket).io.session_reused?
+    session_reused = http.instance_variable_get(:@socket).io.session_reused?
+    assert_true session_reused unless session_reused.nil? # can not detect re-use under JRuby
     assert_equal $test_net_http_data, http.get("/").body
     http.finish
   end
@@ -301,7 +303,7 @@ def test_max_version
     ex = assert_raise(OpenSSL::SSL::SSLError){
       http.request_get("/") {|res| }
     }
-    re_msg = /\ASSL_connect returned=1 errno=0 |SSL_CTX_set_max_proto_version/
+    re_msg = /\ASSL_connect returned=1 errno=0 |SSL_CTX_set_max_proto_version|No appropriate protocol/
     assert_match(re_msg, ex.message)
   end