Reimplement svn_checksum_dup().
Reimplement svn_checksum_dup().

* subversion/libsvn_subr/checksum.c
  (svn_checksum_dup):
    Reimplement using checksum_create().

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion