The ornamental design for the strut cover, as shown and described.
FIG. 1 is a perspective view of the strut cover shown in an environment of use depicted in broken lines;
FIG. 2 is a perspective view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a left side view thereof;
FIG. 7 is a rear elevation view thereof; and,
FIG. 8 is a front elevation view thereof.
The broken lines depicting a car in FIG. 1 are included to show environmental structure; the broken lines depicting the top and bottom of the running horse feature are included to show portions of the article; the peripheral broken line on the bottom surface of the strut cover defines the boundaries of the claimed design; all broken lines form no part of the claimed design.