Bug fix follow up to r1053140 when SVN_ERR__TRACING isn't defined.
Bug fix follow up to r1053140 when SVN_ERR__TRACING isn't defined.

Found by: danielsh

* subversion/tests/libsvn_subr/error-test.c
  (test_error_purge_tracing):
    Only assert when SVN_ERR__TRACING is defined that
    svn_error_return() returns tracing error links.

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