The ornamental design for a gascontainershroud, as shown and described.
FIG. 1 is a front right perspective view of a gas container shroud;
FIG. 2 is a rear left perspective view thereof;
FIG. 3 is a rear right perspective view thereof;
FIG. 4 is a front left perspective view thereof;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a rear elevation view thereof;
FIG. 7 is a left elevation view thereof;
FIG. 8 is a right elevation view thereof;
FIG. 9 is a top plan view thereof; and,
FIG. 10 is a bottom plan view thereof.
The broken lines immediately adjacent the shaded areas and undefined unshaded areas represent the bounds of the claimed design, while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.