astobj.h: Remove from Asterisk core.

This is the old ASTOBJ macro's which are no longer used except by the
deprecated netsock.c.  Move it to the chan_iax2 include folder so it
does not get used elsewhere.

Change-Id: I7e4ae96678b36b9f41d3cae14b167f110eb5d349

channels/iax2/netsock.c

@@ -46,7 +46,7 @@
 #include "include/netsock.h"
 #include "asterisk/netsock2.h"
 #include "asterisk/utils.h"
-#include "asterisk/astobj.h"
+#include "include/astobj.h"
 
 struct ast_netsock {
 	ASTOBJ_COMPONENTS(struct ast_netsock);