The ornamental design for a augerstopper, as shown and described.
FIG. 1—is a ¾ top perspective view of the auger stopper
FIG. 2—is a ¾ bottom perspective view of the auger stopper
FIG. 3—is a side view of the auger stopper; and,
FIG. 4—is a reduced side view of the auger stopper. The broken line showing of a drill and auger is included for the purpose of illustrating environmental structure only and forms no part of the claimed design.