various problem with entity caps

[misc]

After looking at entity caps xep, ( http://www.xmpp.org/extensions/xep-0115.html ), It seems there is several thing badly implemented

• ftrans is not a plugin or something that can be disactivated, so there is no need to show this as a caps. the goal is to signal caps for this that can be different on different instance of the same cleint, and afaik, every gajim instance uunderstand filetransfert

• chatstates, on the other hand, can be disactivated, so this is dependant on the instance, hence being seen as a caps

• when a disco#info request is send, and the node attribute is set, node should be set on the response too, according to example in the xep

• capability should not be hardcoded in presence stanza, since the goal is to have different caps, based on configuration or plugins

• and node attribute should be set on get discovery request ( http://jabber.org/protocol/disco ), or I think so.

Here is a patch that fix all of this. ( and do some factorisation )

[asterix]

(In [8004]) [misc] fix entity caps behaviour. fixes #3001

[roidelapluie]

(In [8629]) 0.11.2: [misc] fix entity caps behaviour. fixes #3001