mod_smacks: Fix some bugs with smacks-ack-delayed event triggering.
The old code had several flaws which are addressed here.
First of all this fixes the if statement guarding the event generation
There where some timing glitches addressed by this commit as well.
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>