schema parsers BUGFIX infinite loop

incorrect variable used to move via linked list.

Fixes #774
diff --git a/src/tree_schema_helpers.c b/src/tree_schema_helpers.c
index ada61c7..a4a93ee 100644
--- a/src/tree_schema_helpers.c
+++ b/src/tree_schema_helpers.c
@@ -523,7 +523,7 @@
             }
         }
         /* search typedefs in parent's nodes */
-        for (parent = node->parent; parent; parent = node->parent) {
+        for (parent = node->parent; parent; parent = parent->parent) {
             if (lysp_type_match(name, parent)) {
                 LOGVAL(ctx->ctx, LY_VLOG_LINE, &ctx->line, LYVE_SYNTAX_YANG,
                        "Invalid name \"%s\" of typedef - name collision with another scoped type.", name);