Upgrade libgit2 to v1.6.3.
The new version now has git_fs_path_basename_r() which is based
on BSD-2-Clause.
(From OE-Core rev: 16e837f16774893246c028f3d4a588bdc5187094)
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
