Update to 0.42
    
    - New upstream release 0.42
      - added $db->Env method to retrieve environment object from a database object
      - get the tied interface to use truncate in the CLEAR method if available
    - Build with libdb (Berkeley DB 5.x) from Fedora 14 onwards (#612139)
    - Tag BerkeleyDB.pod as %doc
    - Use DESTDIR rather than PERL_INSTALL_ROOT