package.bbclass: add a stub implementation of package_name_hook
do_package() calls package_name_hook so that e.g. debian-style renaming through
debian.bbclass can happen. If there is no class providing a package_name_hook
then this causes "WARNING: Function package_name_hook doesn't exist" every time
do_package() is executed.
Silence this warning by providing an empty package_name_hook in package.bbclass.
Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Saul Wold <sgw@linux.intel.com>
