mod_rest: Use logger of HTTP request in trunk
In Prosody trunk rev c975dafa4303 each HTTP request gained its own log
sink, to make it easy to log things related to each request and group
those messages. Especially where async is used, spreading the request
and response apart as mod_rest does with iq stanzas, this grouped
logging should help find related messages.
Contributing
============
Guidelines for developers
-------------------------
- Each module should be contained in a folder of its name (e.g.\
`mod_ping/mod_ping.lua`)
- Each module should have a `README.markdown` page in their folder
with a description, usage, configuration and todo sections (feel
free to copy an existing one as a template)
- Commit messages should begin with the name of the plugin they are
for (e.g. `mod_ping: Set correct namespace on pongs`)
Instructions on cloning the repository are at
<https://prosody.im/doc/installing_modules#prosody-modules>