fix conflict (#1090)

Fix conflict: which has been modified in #1084

Author: dota17

src/test_lib_json/main.cpp

@@ -2258,6 +2258,7 @@ JSONTEST_FIXTURE_LOCAL(StyledStreamWriterTest, multiLineArray) {
                                 "\n\t18,"
                                 "\n\t19,"
                                 "\n\t20\n]\n");
+    Json::StyledStreamWriter writer;
     Json::Value root;
     for (int i = 0; i < 21; i++)
       root[i] = i;