mod_vcard_legacy: Clear avatars on setting a vcard-temp

Otherwise it is not possible to remove avatars

plugins/mod_vcard_legacy.lua

@@ -134,6 +134,10 @@ module:hook("iq-set/self/vcard-temp:vCard", function (event)
 	local vcard4 = st.stanza("item", { xmlns = "http://jabber.org/protocol/pubsub", id = "current" })
 		:tag("vcard", { xmlns = 'urn:ietf:params:xml:ns:vcard-4.0' });
 
+	if pep_service:purge("urn:xmpp:avatar:metadata", origin.full_jid) then
+		pep_service:publish("urn:xmpp:avatar:data", origin.full_jid);
+	end
+
 	vcard4:tag("fn"):text_tag("text", vcard_temp:get_child_text("FN")):up();
 
 	local N = vcard_temp:get_child("N");