feat(handler): change the default tianmu log path from $mysqlhome/log…

…/ to $mysqlhome/data/ stoneatom#609

[summary]
1. "log/tianmu.log" --> "tianmu_engine.log"
2. "trace.log" --> "tianmu_trace.log"
3. "query.log" --> "tianmu_query.log"

storage/tianmu/handler/tianmu_handler_com.cpp

@@ -211,10 +211,10 @@ int rcbase_init_func(void *p) {
   ha_rcengine_ = nullptr;
 
   try {
-    std::string log_file = mysql_home_ptr;
-    log_setup(log_file + "/log/tianmu.log");
-    rc_control_.addOutput(new system::FileOut(log_file + "/log/trace.log"));
-    rc_querylog_.addOutput(new system::FileOut(log_file + "/log/query.log"));
+    std::string log_file = mysql_real_data_home_ptr;
+    log_setup(log_file + "/tianmu_engine.log");
+    rc_control_.addOutput(new system::FileOut(log_file + "/tianmu_trace.log"));
+    rc_querylog_.addOutput(new system::FileOut(log_file + "/tianmu_query.log"));
     struct hostent *hent = nullptr;
     hent = gethostbyname(glob_hostname);
     if (hent)