collectd: fix errormessage on fresh installations

the /etc/collectd.d/ folder must have at least one file in it
so this add an file with a comment that custom configs should placed
there.

Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>

config/rootfiles/common/collectd

@@ -2,7 +2,8 @@ etc/collectd.conf
 etc/collectd.precache
 etc/collectd.thermal
 etc/collectd.vpn
-etc/collectd.d
+#etc/collectd.d
+etc/collectd.d/info
 etc/rc.d/rc0.d/K50collectd
 etc/rc.d/rc3.d/S29collectd
 etc/rc.d/rc6.d/K50collectd

lfs/collectd

@@ -130,6 +130,7 @@ $(TARGET) : $(patsubst %,$(DIR_DL)/%,$(objects))
 		--with-fp-layout=nothing
 	cd $(DIR_APP) && make install #collectd-4 does not support parallel build
 	mkdir /etc/collectd.d
+	echo "# Put custom configfiles in this folder" > /etc/collectd.d/info
 	cp -vf $(DIR_SRC)/config/collectd/collectd.* /etc/
 	mv /etc/collectd.vpn /var/ipfire/ovpn/collectd.vpn
 	chown nobody.nobody /var/ipfire/ovpn/collectd.vpn