OFAgent now has suicidal tendencies.

If OFAgent cannot find voltha-grpc it kills itself only to be restarted
by docker, this will continue until it is happy. Similarly, if voltha
goes away ofagent will kill itself until voltha comes back

Change-Id: Ib2a2cbf5ed438f8bd40f80a4543bd80f065461f1
diff --git a/docker/Dockerfile.ofagent b/docker/Dockerfile.ofagent
index e9a4b84..b5d49f0 100644
--- a/docker/Dockerfile.ofagent
+++ b/docker/Dockerfile.ofagent
@@ -30,6 +30,7 @@
     wget http://ftp.us.debian.org/debian/pool/main/p/protobuf/libprotobuf-dev_3.0.0-9_amd64.deb && \
     wget http://ftp.us.debian.org/debian/pool/main/p/protobuf/libprotobuf10_3.0.0-9_amd64.deb && \
     wget http://ftp.us.debian.org/debian/pool/main/p/protobuf/protobuf-compiler_3.0.0-9_amd64.deb && \
+    wget https://github.com/Yelp/dumb-init/releases/download/v1.2.0/dumb-init_1.2.0_amd64.deb && \
     dpkg -i *.deb && \
     protoc --version && \
     rm -f *.deb
@@ -40,5 +41,7 @@
 COPY common /ofagent/common
 COPY ofagent /ofagent/ofagent
 
+ENTRYPOINT ["/usr/bin/dumb-init", "--"]
+
 # Exposing process and default entry point
-CMD ["python", "ofagent/ofagent/main.py"]
+CMD ["dumb-init", "python", "ofagent/ofagent/main.py"]