Delete Entry from Group List; Delete List if Empty

[krkeegan]

A simple bug fix.

The modem delete db function didn't handle group deletion properly.

This fixes that.

[TD22057]

I'm not sure what to do to trigger this but I'm going to assume you're correct about the bug. I've changed your code from this:

         if entry.is_controller:
            responders = self.groups.setdefault(entry.group, [])
            if entry in responders:
                responders.remove(entry)
            if not responders and entry.group in self.groups:
                del self.groups[entry.group]

to be the following (I don't like adding the empty list if it's not needed)

        if entry.is_controller:
            responders = self.groups.get(entry.group)
            if responders:
                if entry in responders:
                    responders.remove(entry)

            elif entry.group in self.groups:
                del self.groups[entry.group]