Update Digest-SHA to CPAN version 5.83

  [DELTA]

  5.83  Mon Mar  4 08:12:00 MST 2013
    - removed code for standalone C operation (no longer used)
        -- eliminates need for external symbols
        -- consolidates SHA and HMAC code
        -- reduces size of object files
        -- thanks to Marc Lehmann for suggestions
    - tweaked Makefile.PL to show dependencies of SHA.c