Update to 0.53
    
    - correct the default NIS map settings for hosts.byname and hosts.byaddr,
      from report by Rik Megens
    - fix several problems when hitting out-of-memory conditions, spotted by
      static analysis
    - remove ExclusiveArch if %%{rhel} is 7 or higher, because 389-ds-base gets
      built for everything now (#1055711)