libkrb5: replace mkdir with rk_mkdir in dcache.c

Now that libroken provides rk_mkdir(), use it.

Change-Id: Ibf208e45cc36b85198bcb266267bf4665f32ba2f

lib/krb5/dcache.c

@@ -209,7 +209,7 @@ verify_directory(krb5_context context, const char *path)
     if (stat(path, &sb) != 0) {
 	if (errno == ENOENT) {
 	    /* XXX should use mkdirx_np()  */
-	    if (mkdir(path, S_IRWXU) == 0)
+	    if (rk_mkdir(path, S_IRWXU) == 0)
 		return 0;
 
 	    krb5_set_error_message(context, ENOENT,