The ornamental design for a latrine, as shown and described.
FIG. 1 is an exploded perspective view of a latrine, showing our new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a front elevation view thereof; and,
FIG. 4 is a right side elevational view thereof; the left side being a mirror image thereof. The toilet is shown in dotted lines for environmental purposes only and forms no part of the claimed design.