_get_linux_packages function needs updating

Looking at the update-manager bzr branch In UpdateManager/Core/UpdateList.py we can see the following:

    def _get_linux_packages(self):
        "Return all binary packages made by the linux-meta source package"
        # Hard code this rather than generate from source info in cache because
        # that might only be available if we have deb-src lines. I think we
        # could also generate it by iterating over all the binary package info
        # we have, but that is costly. These don't change often.
        return ['linux', 'linux-image', 'linux-headers-generic',
                'linux-image-generic', 'linux-generic',
                'linux-headers-generic-pae', 'linux-image-generic-pae',
                'linux-generic-pae', 'linux-headers-omap', 'linux-image-omap',
                'linux-omap', 'linux-headers-server', 'linux-image-server',
                'linux-server', 'linux-signed-image-generic',
                'linux-signed-generic', 'linux-headers-virtual',
                'linux-image-virtual', 'linux-virtual',
                'linux-image-extra-virtual']

This list seems to be a bit out of date and should be updated.