ui: remove unreachable code in vnc_update_client

A previous commit:

  commit 5a8be0f7
  Author: Gerd Hoffmann <kraxel@redhat.com>
  Date:   Wed Jul 13 12:21:20 2016 +0200

    vnc: make sure we finish disconnect

Added a check for vs->disconnecting at the very start of the
vnc_update_client method. This means that the very next "if"
statement check for !vs->disconnecting always evaluates true,
and is thus redundant. This in turn means the vs->disconnecting
check at the very end of the method never evaluates true, and
is thus unreachable code.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NDarren Kenny <darren.kenny@oracle.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20171218191228.31018-3-berrange@redhat.com
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

ui/vnc.c

@@ -969,7 +969,7 @@ static int vnc_update_client(VncState *vs, int has_dirty)
     }
 
     vs->has_dirty += has_dirty;
-    if (vs->need_update && !vs->disconnecting) {
+    if (vs->need_update) {
         VncDisplay *vd = vs->vd;
         VncJob *job;
         int y;
@@ -1030,10 +1030,6 @@ static int vnc_update_client(VncState *vs, int has_dirty)
         return n;
     }
 
-    if (vs->disconnecting) {
-        vnc_disconnect_finish(vs);
-    }
-
     return 0;
 }