Fix for table sqlite_sequence may not be dropped

[flxholle]

Based on razilsh' Fork which already includes a port to AndroidX!!

I don't know why but on my devices the backup-function (SQL to Excel) creates a sheet called "sqlite_sequence". I've never created that table and there's no need to backup it.

So this table is ignored when you backup the sql database and now the restore works again because this table also mustn't be recreated on restore.