vehicle_reader_t cannot read standard makeobj version 11 objects correctly

[Ranran(retired)]

vehicle_reader_t cannot read standard makeobj version 11 objects correctly.
Those objects have corrupted data and will crash when opening the depot dialog or vehicle list dialog.

A fix for this is included in the 2209-std-r10719 branch.

[jamespetts]

Excellent, thank you: now incorporated.