The Monero GUI code was calling `Monero::wallet::setPassword()` on every open/close for some reason,
and the old `store_to()` code called `store_keys()` with `watch_only=false`, even for watch-only wallets.
This caused a bug where the watch-only keys file got saved with with the JSON field `watch_only` set to 0,
and after saving a watch-only wallet once, a user could never open it back up against because `load()` errored out.
This never got brought up before this because you would have to change the file location of the watch-only
wallet to see this bug, and I guess that didn't happen often, but calling the new `store_to()` function with the
new `force_rewrite` parameter set to `true` triggers key restoring and the bug appeared.
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