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: bf71e6ee1812b54ba8afafa9818eb718c3bd2f82)
Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>