Node.js: added reference count increment for the Unit object.

We increase the number to the Unit object so that it lives forever.
This is necessary so that the garbage collector does not delete the Unit object.

src/nodejs/unit-http/http_server.js

@@ -333,6 +333,8 @@ Server.prototype.run_events = function (server, req, res) {
         });
 
         Promise.resolve().then(() => {
+            req.emit("finish");
+
             if (res.finished) {
                 unit_lib.unit_response_end(res);
             }

src/nodejs/unit-http/unit.cpp

@@ -111,6 +111,7 @@ napi_value
 Unit::create(napi_env env, napi_callback_info info)
 {
     Unit         *obj;
+    napi_ref     ref;
     napi_value   target, cons, instance, jsthis;
     napi_status  status;
 
@@ -135,6 +136,11 @@ Unit::create(napi_env env, napi_callback_info info)
             goto failed;
         }
 
+        status = napi_create_reference(env, jsthis, 1, &ref);
+        if (status != napi_ok) {
+            goto failed;
+        }
+
         return jsthis;
     }
 
@@ -149,6 +155,11 @@ Unit::create(napi_env env, napi_callback_info info)
         goto failed;
     }
 
+    status = napi_create_reference(env, instance, 1, &ref);
+    if (status != napi_ok) {
+        goto failed;
+    }
+
     return instance;
 
 failed: