The ornamental design for a sterilecover, as shown and described.
FIG. 1 is a front perspective view of a sterile cover according to our design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a bottom plan view thereof; and,
FIG. 7 is a top plan view thereof.
The dash dot dash broken lines shown in FIGS. 1, 2 & 4-7 and the dash dash broken lines shown in FIG. 6 are for the purpose of illustrating portions of the sterile cover that form no part of the claimed design. None of the broken lines form any part of the claimed design.