nut: Add missing conffiles

We want to include the symlinks to the generated configurations
in conffiles so that if the user replaces them symlinks with
traditional NUT configuration it is preserved across sysupgrade.

Signed-off-by: Daniel F. Dickinson <cshored@thecshore.com>

net/nut/Makefile

@@ -75,7 +75,6 @@ define Package/nut-server/install
 	$(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/share/nut/driver.list $(1)/usr/share/nut/
 	$(INSTALL_DIR) $(1)/etc/config
 	$(INSTALL_CONF) ./files/nut_server $(1)/etc/config/nut_server
-	ln -sf /var/etc/nut/nut.conf $(1)/etc/nut/nut.conf
 	ln -sf /var/etc/nut/ups.conf $(1)/etc/nut/ups.conf
 	ln -sf /var/etc/nut/upsd.users  $(1)/etc/nut/upsd.users
 	ln -sf /var/etc/nut/upsd.conf $(1)/etc/nut/upsd.conf
@@ -96,6 +95,10 @@ $(call Package/nut/description/Default)
 This package contains the common files.
 endef
 
+define Package/nut-common/conffiles
+/etc/nut/nut.conf
+endef
+
 define Package/nut-common/install
 	$(INSTALL_DIR) $(1)/etc/nut
 	$(INSTALL_DIR) $(1)/usr/lib
@@ -120,6 +123,9 @@ endef
 
 define Package/nut-server/conffiles
 /etc/config/nut_server
+/etc/nut/ups.conf
+/etc/nut/upsd.conf
+/etc/nut/upsd.users
 endef
 
 define Package/nut-upsmon
@@ -141,6 +147,7 @@ endef
 
 define Package/nut-upsmon/conffiles
 /etc/config/nut_monitor
+/etc/nut/upsmon.conf
 endef
 
 define Package/nut-upsmon/install