Fix for delete device hangs.
Don't wait for adapter responses for flow update operations holding the device lock.
Amendments:
 Create a completed response instead of using nil.
 Fix ro_core docker builds

Change-Id: I04228c7bee5cf83c493d885c6751fd911a32c4f6
diff --git a/docker/Dockerfile.ro_core b/docker/Dockerfile.ro_core
index 95159bd..52f4ad5 100644
--- a/docker/Dockerfile.ro_core
+++ b/docker/Dockerfile.ro_core
@@ -20,7 +20,7 @@
 # Install required packages
 RUN apk add --no-cache \
         wget=1.20.3-r0 \
-        git=2.20.1-r0 \
+        git=2.20.2-r0 \
         make=4.2.1-r2 \
         build-base=0.5-r1 \
         protobuf=3.6.1-r1 \