We claim the ornamental design for a joint seal, as shown and described.
FIG. 1 is a perspective view of an embodiment of the claimed design;
FIG. 2 is a front view of the claimed design of FIG. 1, with the rear view being a mirror image thereof;
FIG. 3 is a right side view of the claimed design of FIG. 1, with the left side view being a mirror image thereof;
FIG. 4 is a top plan view of the claimed design of FIG. 1;
FIG. 5 is a bottom plan view of the claimed design of FIG. 1;
FIG. 6 is a perspective view of another embodiment of the claimed design;
FIG. 7 is a front view of the claimed design of FIG. 6, with the rear view being a mirror image thereof;
FIG. 8 is a right side view of the claimed design of FIG. 6, with the left side view being a mirror image thereof;
FIG. 9 is a top plan view of the claimed design of FIG. 6; and,
FIG. 10 is a bottom plan view of the claimed design of FIG. 6.
The ornamental design which is claimed is shown in solid lines in the drawings. The broken lines in the drawings are for illustrative purposes only and form no part of the claimed design.