LSM tree lock flag

@agorrod, while I was looking at this, I noticed there was a trivial bug in the LSM tree lock routine (the no-schema flag gets left set if the lock call fails), and based on your email I thought this might be more useful/clearer?

Anyway, seriously, I only coded it up because that was the fastest way to suggest it, feel free to discard the change out of hand without any thought at all, this may just be a horrible idea.