Improve a server error message "Target path does not exist" by reporting what
path it's referring to.

* subversion/libsvn_repos/reporter.c
  (drive): Include the target path in the "Target path does not exist" error.
--This line, and those below, will be ignored--

Index: subversion/libsvn_repos/reporter.c
===================================================================
--- subversion/libsvn_repos/reporter.c	(revision 34281)
+++ subversion/libsvn_repos/reporter.c	(working copy)
@@ -1159,8 +1159,9 @@ drive(report_baton_t *b, svn_revnum_t s_
 
   /* Check if the target path exists first.  */
   if (!*b->s_operand && !(t_entry))
-    return svn_error_create(SVN_ERR_FS_PATH_SYNTAX, NULL,
-                            _("Target path does not exist"));
+    return svn_error_createf(SVN_ERR_FS_PATH_SYNTAX, NULL,
+                             _("Target path '%s' does not exist"),
+                             b->t_path);
 
   /* If the anchor is the operand, the source and target must be dirs.
      Check this before opening the root to avoid modifying the wc. */