mod_sasl2_fast: Fix harmless off-by-one error (invalidates existing tokens!) Problem: This was causing the key to become "<token>--cur" instead of the expected "<token>-cur". As the same key was used by the code to both set and get, it still worked. Rationale for change: Although it worked, it's unintended, inconsistent and messy. It increases the chances of future bugs due to the unexpected format. Side-effects of change: Existing '--cur' entries will not be checked after this change, and therefore existing FAST clients will fail to authenticate until they attempt password auth and obtain a new FAST token. Existing '--cur' entries in storage will not be cleaned up by this commit, but this is considered a minor issue, and okay for the relatively few FAST deployments.

This module adds a `portcheck` command to the [shell][doc:console]
intended for use with health checks, i.e. to check whether Prosody is
listening to all expected ports.

# Usage

After installing and enabling the module a command like this becomes
available:

``` bash
prosodyctl shell "portcheck [::]:5222 *:5222 [::]:5269 *:5269"
```

This would check if the c2s (`5222`) and s2s (`5269`) ports are
available on both IPv6 (`*`) and *Legacy IP*^[often referred to as IPv4].

# Compatibility

Compatible with Prosody **trunk**, will **not** work with 0.11.x or
earlier.