Roll network service to c223f8ca61e4be0f5cdd52108cb98a7f9cb3fe7b.

This picks up the `--clear` flag for flushing the disk cache.

R=qsr@chromium.org

Review URL: https://codereview.chromium.org/1348143003 .

mojo/public/tools/NETWORK_SERVICE_VERSION

diff --git a/mojo/public/tools/NETWORK_SERVICE_VERSION b/mojo/public/tools/NETWORK_SERVICE_VERSION
index 91026c6..2e7c810 100644
--- a/mojo/public/tools/NETWORK_SERVICE_VERSION
+++ b/mojo/public/tools/NETWORK_SERVICE_VERSION
@@ -1 +1 @@
-1b87e90f670ebfee2b55df21b07dc37dc628fe40
+c223f8ca61e4be0f5cdd52108cb98a7f9cb3fe7b