Revert "Make the pthread cond wait in the getwork scheduler a timed wait in case we miss a wakeup."

This reverts commit 47a20fb8e813f427357dd8133f811e45f6892ede.

Wrong fix.
We shouldn't block on no work situations directly from the getwork scheduler itself.
Put the hashfast temperature into the cgpu structure so that it shows up in the devs API call.
Update NEWS
Bump version to 3.12.3