hlr: Export + Declare global g_hlr symbol

It is a global variable, and it's sort of bogus if every C file
re-declares it as a static global variable that is assigned to the
same value as the "real" global one during start-up.

Change-Id: I6f3e50f071fb2fbbe58413b4760dc2215055a444
diff --git a/src/hlr_vty_subscr.c b/src/hlr_vty_subscr.c
index 4092a8f..9ee6948 100644
--- a/src/hlr_vty_subscr.c
+++ b/src/hlr_vty_subscr.c
@@ -33,8 +33,6 @@
 
 #define hexdump_buf(buf) osmo_hexdump_nospc((void*)buf, sizeof(buf))
 
-static struct hlr *g_hlr = NULL;
-
 static void subscr_dump_full_vty(struct vty *vty, struct hlr_subscriber *subscr)
 {
 	int rc;
@@ -476,10 +474,8 @@
 	return CMD_SUCCESS;
 }
 
-void hlr_vty_subscriber_init(struct hlr *hlr)
+void hlr_vty_subscriber_init(void)
 {
-	g_hlr = hlr;
-
 	install_element_ve(&subscriber_show_cmd);
 	install_element(ENABLE_NODE, &subscriber_create_cmd);
 	install_element(ENABLE_NODE, &subscriber_delete_cmd);