spice: fix spice_chr_add_watch() pre-condition

Since e02bc6de, add_watch() is called
with G_IO_HUP. Even if spice-qemu-char ignores this flag, the
precondition must be changed.

https://bugzilla.redhat.com/show_bug.cgi?id=1128992Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

spice-qemu-char.c

@@ -172,7 +172,7 @@ static GSource *spice_chr_add_watch(CharDriverState *chr, GIOCondition cond)
     SpiceCharDriver *scd = chr->opaque;
     SpiceCharSource *src;
 
-    assert(cond == G_IO_OUT);
+    assert(cond & G_IO_OUT);
 
     src = (SpiceCharSource *)g_source_new(&SpiceCharSourceFuncs,
                                           sizeof(SpiceCharSource));