The ornamental design for a bottleopener, as shown and described.
FIG. 1 is a perspective view showing the design for a bottle opener;
FIG. 2 is a perspective view showing the design;
FIG. 3 is a perspective view showing the design;
FIG. 4 is a front elevation view showing the design, the left side, right side, and back elevation views being substantially identical thereto, the sole difference being the positioning of the threading around the bottom edge.
FIG. 5 is a bottom plan view showing the design; and,
FIG. 6 is a top plan view showing the design.
The broken lines depict environmental subject matter only and do not form part of the claimed design.