Had to also fix a couple links in the "migration" chapter due
to the section heading of the packagegroup.bbclass section
changing.
(From yocto-docs rev: 412b8325a13e5bf31d057efb5f6dbb54f8a1aba0)
Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>