Policy-Kit has been replaced by polkit (referred to, respectively,
as POLKIT0 and POLKIT1 in our Makefiles).

The last build fix with old Policy-Kit was in May 2013:
commit <442eb2ba> and build with -Wunused-label was broken
since April 2016: commit <84371303>
Signed-off-by: NJán Tomko <jtomko@redhat.com>