vnc: make sure to send pointer type change event on SetEncodings

Commit 37c34d9d introduced a regression when
using relative mouse mode with a client that understands the PointerTypeChange
pseudo-encoding.
Reported-by: NMarcelo Tosatti <mtosatti@redhat.com>
Reported-by: NGerhard Wiesinger <lists@wiesinger.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

vnc.c

@@ -1642,6 +1642,8 @@ static void set_encodings(VncState *vs, int32_t *encodings, size_t n_encodings)
             break;
         }
     }
+
+    check_pointer_type_change(&vs->mouse_mode_notifier);
 }
 
 static void set_pixel_conversion(VncState *vs)