Instead of fetching all the LFS objects present in the current revision
in a sparse checkout, whether they are needed inside the sparse cone or
not, let's instead only pull the ones that are actually needed.
To do that, let's avoid running that preemptive `git lfs fetch` call in
case of a sparse checkout.
An alternative that was considered during the development of this patch
(and ultimately rejected) was to use `git lfs pull --include <path>...`,
but it turned out to be too inflexible because it requires exact paths,
not the patterns that are available via the sparse checkout definition,
and that risks running into command-line length limitations.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
25d6c12a40