Add missing syslog-sidecar in docker-compose.yaml

Change-Id: Ia8c7a9f7aadc572a29127498644f718b220d049e

src/test/docker/docker-compose.yaml

diff --git a/src/test/docker/docker-compose.yaml b/src/test/docker/docker-compose.yaml
index 8a4eda8..8524963 100644
--- a/src/test/docker/docker-compose.yaml
+++ b/src/test/docker/docker-compose.yaml
@@ -92,6 +92,7 @@
 volumes:
   shareddir:
   nfs-server-volume:
+  syslog-sidecar:
   git-volume:
     driver: "local"
     driver_opts: