Fixes accounts lt hash verification at startup

[brooksprumo]

Problem

When testing out accounts lt hash startup verification, if the accounts lt hash verification fails when running in the background, we don't panic/bring down the whole node.

This is because of the early returns.

After the background verification ends, we need to call .background_finished(). Otherwise we'll continue waiting on the result of the verification. I introduced the early returns in a previous PR, and so if the verification fails we'll never call background_finished() and thus are never notified.

Summary of Changes

Remove the early returns so that background_finished() is always called.

[jeffwashington]

lgtm

[HaoranYi]

lgtm.

looks like it is a good candidate for "Drop" guard - we could introduce a VerificationFinishGuard and when it drops, call background_finished().