printer json BUGFIX escaped chars in opaque value

Fixes #2034
diff --git a/tests/utests/data/test_parser_json.c b/tests/utests/data/test_parser_json.c
index d2c40e6..9e99e34 100644
--- a/tests/utests/data/test_parser_json.c
+++ b/tests/utests/data/test_parser_json.c
@@ -520,6 +520,12 @@
     CHECK_LYD_STRING(tree, LYD_PRINT_SHRINK | LYD_PRINT_WITHSIBLINGS, data);
     lyd_free_all(tree);
 
+    /* special chars */
+    data = "{\"a:foo3\":\"ab\\\"\\\\\\r\\t\"}";
+    CHECK_PARSE_LYD(data, LYD_PARSE_OPAQ | LYD_PARSE_ONLY, 0, tree);
+    CHECK_LYD_STRING(tree, LYD_PRINT_SHRINK | LYD_PRINT_WITHSIBLINGS, data);
+    lyd_free_all(tree);
+
     /* missing key, no flags */
     data = "{\"a:l1\":[{\"a\":\"val_a\",\"b\":\"val_b\",\"d\":\"val_d\"}]}";
     PARSER_CHECK_ERROR(data, 0, LYD_VALIDATE_PRESENT, tree, LY_EVALID,