locks with ttls are broken

[Roguelazer]

In the _acquired function of lock.py, the code first sets a key, then calls watch with no timeout. If the lock is held by a peer who ever calls renew(), this causes an uncaught exception.

Specifically, if you're using TTLs, the key might expire before the watch returns, which causes the later call to _acquired to fail.

The whole idea of having a recursive function which contains an infinite loop is kind of hinky.