collectd: adjust dependecies for iptables bump

iptables 1.8.4 drops support for a combined libiptc, providing split
libip4tc & libip6tc instead.  Adjust collectd dependencies in advance of
iptables bump from 1.8.3 to 1.8.4

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>

utils/collectd/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=collectd
 PKG_VERSION:=5.10.0
-PKG_RELEASE:=3
+PKG_RELEASE:=4
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=https://collectd.org/files/ \
@@ -382,7 +382,7 @@ $(eval $(call BuildPlugin,exec,process exec input,exec,))
 $(eval $(call BuildPlugin,filecount,file count input,filecount,))
 $(eval $(call BuildPlugin,fscache,file-system based caching framework input,fscache,))
 $(eval $(call BuildPlugin,interface,network interfaces input,interface,))
-$(eval $(call BuildPlugin,iptables,iptables status input,iptables,+PACKAGE_collectd-mod-iptables:iptables +libiptc))
+$(eval $(call BuildPlugin,iptables,iptables status input,iptables,+PACKAGE_collectd-mod-iptables:iptables +libip4tc +libip6tc))
 $(eval $(call BuildPlugin,irq,interrupt usage input,irq,))
 $(eval $(call BuildPlugin,iwinfo,libiwinfo wireless statistics,iwinfo,+PACKAGE_collectd-mod-iwinfo:libiwinfo))
 $(eval $(call BuildPlugin,load,system load input,load,))