The ornamental design for the rack dolly fitting, as shown and described.
FIG. 1 is a top perspective view of the rack dolly fitting showing our new design.
FIG. 2 is a bottom perspective view thereof.
FIG. 3 is a front elevational view thereof.
FIG. 4 is a rear elevational view thereof.
FIG. 5 is a left side elevational view thereof.
FIG. 6 is a right side elevational view thereof.
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines showing the castors, nuts and bolts, and circular broken lines on the fitting, illustrate portions of the rack dolly fitting that form no part of the claimed design.