replay: allow replay stopping and restarting

This patch fixes bug with stopping and restarting replay
through monitor.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20160926080815.6992.71818.stgit@PASHA-ISP>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/cpus.c b/cpus.c
index fbd70f5..b2fbe33 100644
--- a/cpus.c
+++ b/cpus.c
@@ -750,6 +750,7 @@
     }
 
     bdrv_drain_all();
+    replay_disable_events();
     ret = blk_flush_all();
 
     return ret;