chapter300, [SORA] We have fixed the exclusive lock of database processing.

One of the rare cause of wallet corruption is to the exclusive lock on the database that is not working properly.
Therefore, this time, we will fix all “encapsulation” and thoroughly review around locks to ensure that the exclusive lock works.

https://github.com/FromHDDtoSSD/SorachanCoin-qt/blob/master/src/db.h