SSSCTL: Use get_ prefix for the sssctl_attr_fn functions
As done for the attr_name_fn to avoid "-Wshadow", let's be consistent
and do the same for all the other sssctl_attr_fn functions.
Signed-off-by: Fabiano Fidêncio <fidencio@redhat.com>
Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>