swig-pl: Add tests for using a _p_svn_opt_revision_t directly.

* subversion/bindings/swig/perl/native/t/3lient.t
  (log2): Add tests for log2 that compares the log output between
    a more perlish method of specificying the rev with a manually
    created _p_svn_opt_revision_t.

Patch by: Roderich Schupp <roderich.schupp{_AT_}gmail.com>
          me
(I took Roderich's patch and moved it to 3client.t and created the
_p_svn_opt_revision_t values directly rather than via
parse_externals_description3())


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1446761 13f79535-47bb-0310-9956-ffa450edef68