Favor pointers over references

The use of a pointer instead of a reference conveys the message that the
lifetime of the object being pointed can, and most likely will, exceed the
lifetime of the function.

Also shuffled the member variables and internal functions around and
removed unneeded function declarations.

server/modules/routing/schemarouter/schemarouterinstance.hh

@@ -39,9 +39,13 @@ public:
     void diagnostics(DCB* pDcb);
     uint64_t getCapabilities();
 
-protected:
+private:
     friend class SchemaRouterSession;
 
+    /** Internal functions */
+    SchemaRouter(SERVICE *service, char **options);
+
+    /** Member variables */
     schemarouter_config_t m_config;        /*< expanded config info from SERVICE */
     ShardManager          m_shard_manager; /*< Shard maps hashed by user name */
     SERVICE*              m_service;       /*< Pointer to service */
@@ -54,6 +58,4 @@ protected:
                                             * not cause the session to be terminated
                                             * if they are found on more than one server. */
     pcre2_match_data*     m_ignore_match_data;
-
-    SchemaRouter(SERVICE *service, char **options);
 };