update to const hg_info retval

examples/margo-example-client.c

@@ -192,7 +192,7 @@ static void run_my_rpc(void *_arg)
     int ret;
     hg_size_t size;
     void* buffer;
-    struct hg_info *hgi;
+    const struct hg_info *hgi;
 
     printf("ULT [%d] running.\n", arg->val);
 

examples/my-rpc.c

@@ -27,7 +27,7 @@ static void my_rpc_ult(hg_handle_t handle)
     hg_size_t size;
     void *buffer;
     hg_bulk_t bulk_handle;
-    struct hg_info *hgi;
+    const struct hg_info *hgi;
 #if 0
     int fd;
     char filename[256];
@@ -88,7 +88,7 @@ DEFINE_MARGO_RPC_HANDLER(my_rpc_ult)
 static void my_rpc_shutdown_ult(hg_handle_t handle)
 {
     hg_return_t hret;
-    struct hg_info *hgi;
+    const struct hg_info *hgi;
     margo_instance_id mid;
 
     printf("Got RPC request to shutdown\n");

include/margo.h

@@ -199,7 +199,7 @@ hg_return_t __name##_handler(hg_handle_t handle) { \
     int __ret; \
     ABT_pool* __pool; \
     margo_instance_id __mid; \
-    struct hg_info *__hgi; \
+    const struct hg_info *__hgi; \
     __hgi = HG_Get_info(handle); \
     __mid = margo_hg_class_to_instance(__hgi->hg_class); \
     __pool = margo_get_handler_pool(__mid); \