Teach UploadPack to advertise the filter capability and support a
"filter" line in the request, accepting blob sizes only, if the
configuration variable "uploadpack.allowfilter" is true. This feature is
currently in the "master" branch of Git, and as of the time of writing,
this feature is to be released in Git 2.17.
This is incomplete in that the filter-by-sparse-specification feature
also supported by Git is not included in this patch.
If a JGit server were to be patched with this commit, and a repository
on that server configured with RequestPolicy.ANY or
RequestPolicy.REACHABLE_COMMIT_TIP, a Git client built from the "master"
branch would be able to perform a partial clone.
Change-Id: If72b4b422c06ab432137e9e5272d353b14b73259
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>