rpm: obsolete old libwicked0 library name
rpm: removed obsolete pkgconfig(systemd), use unitdir
lib: expose ni_netdev_name_is_valid utility

This function is supposed to check netdev names for disallowed
characters or blacklisted special purpose names like "default"
and "all" used in sysfs.
client: moved client/policy.c to sources
nanny: reject policies with invalid name
ifdown: reenabled to remove nanny policies on down
nanny: encode policy names as required for dbus

TODO: get rid of the use of interface names as policy
      names and use [policy]%u in the object path.
Merge pull request #278 from mtomaschewski/nanny

nanny: reject policies with invalid name