When OPEC and Russia meet this weekend to gauge progress on their oil-supply deal, they’ll be trying to dispel the shadow of previous unfulfilled promises. Oil prices rose 20 percent in the month after OPEC agreed to cut output, reaching $54.06 a barrel in New York on Dec. 28. Since then, they’ve slipped almost 5 percent as traders, with one eye on rising U.S. shale production, await proof that OPEC and other producers will live up to their deal.