Revert "Semi-Merge commit '0b6ee62' into cg_merges_20130524b (just skip rehashing data in submission)"

This reverts commit a43e46d8f2285256a34d14c7f52cf2e7a4133ca4, reversing
changes made to 523c449c0e14abe587315eac7bb65deeb5f36dc6.

rebuild_hash does the block check

miner.c

@@ -3995,6 +3995,8 @@ static struct submit_work_state *begin_submission(struct work *work)
 		.work = work,
 	};
 
+	rebuild_hash(work);
+
 	if (stale_work(work, true)) {
 		work->stale = true;
 		if (opt_submit_stale)