On the 1.7.x-issue4340 branch, filter control characters from an error message.

This corresponds to r1481627 on trunk, but the svn_path_illegal_path_escape()
API function used in that commit is not available in 1.7.x. So I've manually
marked the revision as merged using a --record-only merge.

* subversion/libsvn_fs_fs/tree.c
  (): Include svn_ctype.h for svn_ctype_iscntrl().
  (escape_newline): Rename to...
  (illegal_path_escape): ... this, and tweak the code to match the current
   implementation of svn_path_illegal_path_escape() on trunk.
  (check_newline): Update caller.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.7.x-issue4340@1481817 13f79535-47bb-0310-9956-ffa450edef68