Ensure that we have LOG_log locked when relay_log.close is called

If open of the relay log failed, we got an assert in MYSQL_BIN_LOG::close
This only affected DEBUG systems

sql/rpl_rli.cc

@@ -122,11 +122,14 @@ int init_relay_log_info(Relay_log_info* rli,
   int info_fd;
   const char* msg = 0;
   int error = 0;
+  mysql_mutex_t *log_lock;
   DBUG_ENTER("init_relay_log_info");
   DBUG_ASSERT(!rli->no_storage);         // Don't init if there is no storage
 
   if (rli->inited)                       // Set if this function called
     DBUG_RETURN(0);
+
+  log_lock= rli->relay_log.get_log_lock();
   fn_format(fname, info_fname, mysql_data_home, "", 4+32);
   mysql_mutex_lock(&rli->data_lock);
   info_fd = rli->info_fd;
@@ -208,7 +211,6 @@ a file name for --relay-log-index option", opt_relaylog_index_name);
     Master_info* mi= rli->mi;
     char buf_relay_logname[FN_REFLEN], buf_relaylog_index_name_buff[FN_REFLEN];
     char *buf_relaylog_index_name= opt_relaylog_index_name;
-    mysql_mutex_t *log_lock;
 
     create_logfile_name_with_suffix(buf_relay_logname,
                                     sizeof(buf_relay_logname),
@@ -228,7 +230,6 @@ a file name for --relay-log-index option", opt_relaylog_index_name);
       note, that if open() fails, we'll still have index file open
       but a destructor will take care of that
     */
-    log_lock= rli->relay_log.get_log_lock();
     mysql_mutex_lock(log_lock);
     if (rli->relay_log.open_index_file(buf_relaylog_index_name, ln, TRUE) ||
         rli->relay_log.open(ln, LOG_BIN, 0, 0, SEQ_READ_APPEND,
@@ -306,7 +307,9 @@ Failed to open the existing relay log info file '%s' (errno %d)",
         if (info_fd >= 0)
           mysql_file_close(info_fd, MYF(0));
         rli->info_fd= -1;
+        mysql_mutex_lock(log_lock);
         rli->relay_log.close(LOG_CLOSE_INDEX | LOG_CLOSE_STOP_EVENT);
+        mysql_mutex_unlock(log_lock);
         mysql_mutex_unlock(&rli->data_lock);
         DBUG_RETURN(1);
       }
@@ -437,8 +440,12 @@ Failed to open the existing relay log info file '%s' (errno %d)",
   if (info_fd >= 0)
     mysql_file_close(info_fd, MYF(0));
   rli->info_fd= -1;
+
+  mysql_mutex_lock(log_lock);
   rli->relay_log.close(LOG_CLOSE_INDEX | LOG_CLOSE_STOP_EVENT);
+  mysql_mutex_unlock(log_lock);
   mysql_mutex_unlock(&rli->data_lock);
+
   DBUG_RETURN(1);
 }