Finish issue #2471 ('Invalid control character' error message outputs unescaped control characters) by, well, escaping the path before including it in the error message.
Finish issue #2471 ('Invalid control character' error message outputs
unescaped control characters) by, well, escaping the path before
including it in the error message.

* subversion/libsvn_subr/path.c
  (illegal_path_escape): New.
  (svn_path_check_valid): Use illegal_path_escape() to escape the
    illegal path as presented in the error message.

Patch by: cmpilato

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