pidgin/ljfisher-ssl-client-auth

Suppress error spews when we've left an IRC channel but the window is open.

My take on a patch from Florian Quèze to fix yet another IRC WHO problem.
BOOLEAN:VOID
BOOLEAN:STRING
VOID:INT,INT,INT,INT
VOID:INT,INT
VOID:POINTER,POINTER
BOOLEAN:INT,INT
BOOLEAN:INT,INT,INT
BOOLEAN:POINTER,POINTER,POINTER
BOOLEAN:INT,INT,INT,POINTER
VOID:STRING,STRING
VOID:POINTER,BOOLEAN