Remove redundant check for NULL in sshfwd_close(). The thing we're

testing against NULL has already been dereferenced by the time we
bother to test it, so it's a bit pointless - and in any case, no
null pointer can come to this function from any existing call site.

[originally from svn r8990]

ssh.c

@@ -4164,7 +4164,7 @@ void sshfwd_close(struct ssh_channel *c)
     if (ssh->state == SSH_STATE_CLOSED)
 	return;
 
-    if (c && !c->closes) {
+    if (!c->closes) {
 	/*
 	 * If halfopen is true, we have sent
 	 * CHANNEL_OPEN for this channel, but it hasn't even been