The ornamental design for a bootbottleholder, as shown and described.
FIG. 1 shows a front left-side view of a boot bottle holder;
FIG. 2 shows a top view thereof;
FIG. 3 shows a left-side view thereof;
FIG. 4 shows a front view thereof;
FIG. 5 shows a rear view thereof;
FIG. 6 shows a right-side view thereof; and,
FIG. 7 shows a bottom view thereof.
The dotted lines illustrate stitching which is not part of the claimed design and forms no part of the design to be patented. The dashed-lines on the sole and heel form no part of the design to be patented.