FastCFS v3.4 released

After a month and a half of intensive development and testing, v3.4 was released with following main improvements:

1. introduce vote node to prevent brain splitting in 2 data copies (i.e. dual active & standby & avoid brain splitting to ensure data consistency);
2. binlog dedup and historical data cleaning of fdir and fstore to reduce unnecessary disk space occupation;
3. fdir's file lock implemented strictly follows POSIX specification:

1. allow re-entry (repeatedly locking in the same process);
2. unlock returns success anyway;
3. one unlock can unlock many locks;
4. unlock supports partial unlocking.

4. remove unnecessary error logs and add the service name to the network connection failure log for problem location.

The fixed bugs are:
[fdir] bugfixed: must check load children for list dentry when storage engine is enabled
[fdir] bugfixed: CAS set data version correctly
[fdir] bugfixed: MUST change replication ptr array in the cluster thread
[fauth] bugfixed: padding with the terminating '\0' character for strtoll
[fstore] bugfixed: send active test when (task->offset == 0 && task->length == 0)