Follow-up to r1897452: Fix 'make check' under Python 3.

Found by: julianfoad

* subversion/tests/cmdline/svntest/main.py
  (run_command_stdin): Don't refer to 'unicode' under Python 3.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1897503 13f79535-47bb-0310-9956-ffa450edef68
1 file changed