Bug#29993 (Default value of log_output should be 'FILE', not 'TABLE')

Changed the default location of the log output to LOG_FILE,
for backward compatibility with MySQL 5.0

mysql-test/r/log_state.result

@@ -131,7 +131,7 @@ set global general_log=ON;
 set global log_output=default;
 show variables like 'log_output';
 Variable_name	Value
-log_output	TABLE
+log_output	FILE
 set global general_log=OFF;
 set global log_output=FILE;
 truncate table mysql.general_log;

sql/set_var.cc

@@ -2220,9 +2220,9 @@ void sys_var_log_output::set_default(THD *thd, enum_var_type type)
 {
   pthread_mutex_lock(&LOCK_global_system_variables);
   logger.lock();
-  logger.init_slow_log(LOG_TABLE);
-  logger.init_general_log(LOG_TABLE);
-  *value= LOG_TABLE;
+  logger.init_slow_log(LOG_FILE);
+  logger.init_general_log(LOG_FILE);
+  *value= LOG_FILE;
   logger.unlock();
   pthread_mutex_unlock(&LOCK_global_system_variables);
 }