udev-cache: choose a more descriptive cache filename
"/etc/dev.tar.gz" doesn't adequately imply that udev-cache maintains it.
Instead, call it "/etc/udev-cache.tar.gz".
Signed-off-by: Richard Tollerton <rich.tollerton@ni.com> Signed-off-by: Ben Shelton <ben.shelton@ni.com> Acked-by: Gratian Crisan <gratian.crisan@ni.com> Acked-by: Otavio Salvador <otavio@ossystems.com.br> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
