xinetd: save configurations in /etc/xinetd.d on sysupgrade

For applications writing their own xinetd configuration to the /etc/xinetd.d
directory it would be necessary to save them (e.g. a user edits them manually)

Signed-off-by: Helge Mader <ma@dev.tdt.de>

net/xinetd/Makefile

@@ -41,6 +41,7 @@ endef
 
 define Package/xinetd/conffiles
 /etc/config/xinetd
+/etc/xinetd.d
 endef
 
 TARGET_CFLAGS += -DNO_RPC