votequorum.c: add "const" to avoid 2 more warnings

git-svn-id: http://svn.fedorahosted.org/svn/corosync/trunk@1938 fd59a12c-fef9-0310-b244-a6a79926bd2f

include/corosync/engine/coroapi.h

@@ -43,7 +43,7 @@
 typedef void * corosync_timer_handle_t;
 
 struct corosync_tpg_group {
-	void *group;
+	const void *group;
 	int group_len;
 };