Fix the HELPOP database being destroyed when a rehash fails.
Merge pull request #714 from SaberUK/insp20+fix-helpop

[2.0] Fix the HELPOP database being destroyed when a rehash fails.
Show +i users on a channel to opers having the channels/auspex priv who do /NAMES from outside of the chan

Discovered by @Cronus89
Fix possible use of invalid iterator on module unload

When a module quits a user or destroys a channel in OnCleanup() the object is no longer in the container being iterated by the time OnCleanup() returns
m_mlock Only deny the mlocked mode from being changed instead of denying the entire mode change if it contains a single mlocked mode

Fixes issue #615 reported by @BlacklightShining
m_sajoin Send global snotice when the join happens

Remove "sent remote SAJOIN" local snotice

Fixes issue #382 reported by @JDowny