As previously implemented the `uid` and `gid` fields could only ever be
read as 0, because they were being initialized to zero and then
memoization (`@uid ||= uid`) was used to 'save' the new value. Using `nil`
as the initial value for either of these fields breaks so many tests, so I
have fixed this by not using memoization instead. This is safe because it
is only the local extra field that holds these values for this type of
extra field.
Robert Haines
Pavel Lobashov
Pavel.Lobashov
Alexander Simonov