astobj2: Fix shutdown order.

When REF_DEBUG and AO2_DEBUG are both enabled we closed the refs log
before we shutdown astobj2_container.  This caused the AO2_DEBUG
container registration container to be reported as a leak.

Change-Id: If9111c4c21c68064b22c546d5d7a41fac430430e

main/astobj2.c

@@ -887,8 +887,11 @@ int astobj2_init(void)
 	}
 #endif
 
+	ast_register_cleanup(astobj2_cleanup);
+
 	if (container_init() != 0) {
 		fclose(ref_log);
+		ref_log = NULL;
 		return -1;
 	}
 
@@ -896,7 +899,5 @@ int astobj2_init(void)
 	ast_cli_register_multiple(cli_astobj2, ARRAY_LEN(cli_astobj2));
 #endif	/* defined(AO2_DEBUG) */
 
-	ast_register_cleanup(astobj2_cleanup);
-
 	return 0;
 }