For future reference, you can goto the URL opera://password-manager/settings and export your passwords to a CSV file, open the file up in a text editor to make sure they're there and then copy the file to a USB stick. Then, in the new Opera, you can goto opera://password-manager/settings and import that CSV file to get your passwords back.
It's always good to have that way as a backup just in case things don't work out with Sync.