Fix a bug in the pre-0.14 dumpstream parsing code. Correctly handle file modification to contain no content. Followup to r12075
Fix a bug in the pre-0.14 dumpstream parsing code. Correctly handle file
modification to contain no content. Followup to r12075

* subversion/libsvn_repos/load.c (svn_repos_parse_dumpstream2): When an old-v1
    dumpstream block is detected with zero bytes of content after the property
    block, correctly deduce whether this is an empty text block or an absent
    text block.

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