mod_smacks: Bounce unhandled stanzas from local origin (fix #1759)
Sending stanzas with a remote session as origin when the stanzas have a
local JID in the from attribute trips validation in core.stanza_router,
leading to warnings:
> Received a stanza claiming to be from remote.example, over a stream authed for localhost.example
Using module:send() uses the local host as origin, which is fine here.