Count unix sockets when counting client listeners
In legacy/trac#17178 (moved), we discovered that unix sockets aren't being counted for the client listener *_set options (like SOCKSPort_set). This is required for correct behaviour in legacy/trac#17178 (moved).
These variables aren't ever used, so this fix is not user-visible.
I'm just opening this to get a bug number, the fix is in the legacy/trac#17178 (moved) branch.