The ornamental design for a cover for a passagewaydoor lock, as shown and described.
FIG. 1 is a perspective view of a cover for a passageway door lock showing my design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left elevational view thereof;
FIG. 5 is a right elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view thereof, shown in its environmental use; the broken lines illustrating a press bar, a housing, and latch are for illustrative purpose only and form no part of the claimed design.