CALGARY—Sheldon Keefe had 30 seconds to settle things down. The Maple Leafs head coach had just watched Toronto’s anemic power play—one loaded with talent, but stuck in neutral on a mystifying 0-for-29 run the last three weeks—surrender a short-handed goal to tie Monday’s game 3-3 midway through the third period. There was still time for the Leafs to operate at 5 on 4, however, so Keefe sent the No. 1 unit back over the boards after calling his timeout in hopes they would regroup and make amends. “It’s probably as rock bottom as the power play can get the way it’s been going,” he explained. “The guys responded beautifully.” Auston Matthews scored his second goal of the night on that man advantage to increase his NHL-best total to 27 and Jack Campbell made 26 saves to equal a franchise record with his ninth straight win as Toronto defeated the Calgary …