Fixes for Docker build

- add runtime dependency on git
- set ONOS_ROOT before doing build
- Add top level directory to grpc proto compiler include directories

Change-Id: I6e7a119a122f708988cce28090c9bc7011808b78
diff --git a/Dockerfile b/Dockerfile
index 420074c..ed5242d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -18,10 +18,14 @@
 COPY . /src/onos/
 
 # Build ONOS
+# FIXME - dependence on ONOS_ROOT and git at build time is a hack to work around
+# build problems
 WORKDIR /src
 RUN     apt-get update && \
-        apt-get install -y python less zip curl oracle-java8-installer oracle-java8-set-default ssh && \
+        apt-get install -y python less zip curl oracle-java8-installer oracle-java8-set-default ssh git && \
         cd onos && \
+        ONOS_ROOT=/src/onos && \
+        export ONOS_ROOT && \
         tools/build/onos-buck build onos && \
         cp buck-out/gen/tools/package/onos-package/onos.tar.gz /tmp/ && \
         cd .. && \