revid: deadlock when error happens in setupPipeline

[Trek Hopton]

In the revid setup process, if an error happens in the setupPipeline function eg. setupAudio returns an error, it causes a deadlock instead of stopping revid and logging the error: setupPipeline returns the err to → reset → Start which calls r.mu.Lock() then r.Stop(), the deadlock happens when Stop() calls r.IsRunning() which also calls r.mu.Lock(). r.IsRunning deadlocks because r.mu is still locked by the call in r.Start.

[Saxon Milton]

Resolved by PR #433