Remove declared ledGroups variables from json-parser.hpp

Since not all companies use ledManager to enable `use-json` by
default, the declaration of ledGroups should not be defined in
the json-parser.hpp file.
Here we use hard-coded way to declare ledGroups.

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: I7def887614b246f74dbd0739d563f01661b1f8f8
diff --git a/manager/led-main.cpp b/manager/led-main.cpp
index 5182523..f12dd20 100644
--- a/manager/led-main.cpp
+++ b/manager/led-main.cpp
@@ -45,7 +45,8 @@
     phosphor::led::Manager manager(bus, systemLedMap);
 
     /** @brief sd_bus object manager */
-    sdbusplus::server::manager_t objManager(bus, ledGroups);
+    sdbusplus::server::manager_t objManager(bus,
+                                            "/xyz/openbmc_project/led/groups");
 
     /** @brief vector of led groups */
     std::vector<std::unique_ptr<phosphor::led::Group>> groups;