Merge pull request #2205 from nicolasnoble/threadpools-need-to-cascade-kick

Cascade-kick pollsets when shutting down.
diff --git a/src/core/surface/completion_queue.c b/src/core/surface/completion_queue.c
index bd0fabf..063a23c 100644
--- a/src/core/surface/completion_queue.c
+++ b/src/core/surface/completion_queue.c
@@ -208,6 +208,7 @@
     }
     if (cc->shutdown) {
       ev = create_shutdown_event();
+      grpc_pollset_kick(&cc->pollset);
       break;
     }
     if (!grpc_pollset_work(&cc->pollset, deadline)) {