Allow docker build to set the git hash based version string

Change-Id: Ia9db74bfcaea9eb1fc91bdfb1941f00a86e7c964
(cherry picked from commit 50e43f030632df9b1f9797b5344f51f6cb25999a)
diff --git a/.dockerignore b/.dockerignore
index f78caff..24b8dc4 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -8,7 +8,6 @@
 .buckd
 buck-out
 bucklets/plugins
-.git
 bin
 
 web/gui/src/main/webapp/tests/node_modules
diff --git a/Dockerfile b/Dockerfile
index 51b1a58..a4709b8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -22,7 +22,7 @@
         mkdir -p /src/tar && \
         cd /src/tar && \
         tar -xf /src/onos/buck-out/gen/tools/package/onos-package/onos.tar.gz --strip-components=1 && \
-        rm -rf /src/onos/buck-out
+        rm -rf /src/onos/buck-out .git
 
 
 # Second stage is the runtime environment