package_ipk: Use localdata store when signing packages

When signing a package, we were resolving the `PKGV` version using the
original data store (`d`). However, since that store does not have the
package name in its `OVERRIDES` list the wrong version can be returned in
recipes that produce multiple packages. One such example would be
`external-arm-toolchain.bb`.

The above issue is fixed by using `localdata` instead of `d` when
resolving the needed variables.

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@verkada.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>