Set min version for objective c code
Set min version for objective c code

(cherry picked from commit d2d09e8fcc860e1402cc31955475a081e3f2cad2)

uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend