CANADA STOCKS-TSX slips as energy shares drop with oil price

* TSX down 38.83 points, or 0.25 percent, at 15,416.21 * Seven of 10 main index sectors decline * Mining stocks weaken on volatile commodity prices By John Tilak TORONTO, July 28 (Reuters) - Canada's main stock index fell on Monday as weakness in the price of oil dragged on shares of energy producers such as Suncor Energy Inc and Canadian Natural Resources Ltd. While signs of increasing supply and sluggish demand played the biggest role in pushing crude oil prices lower, inv