pegging docker build to debian jessie

Change-Id: I43e230c1ddbbe2d8f513f985b898eb255b357207
diff --git a/tools/build/docker/Dockerfile b/tools/build/docker/Dockerfile
index ef9533e..b0c54b2 100644
--- a/tools/build/docker/Dockerfile
+++ b/tools/build/docker/Dockerfile
@@ -1,4 +1,4 @@
-FROM debian
+FROM debian:jessie
 MAINTAINER Ali Al-Shabibi <ali@onlab.us>
 
 # Add Java 8 repository