Fix PATH environment variable for Accumulo bin directory (#19)

diff --git a/Dockerfile b/Dockerfile
index d776c19..e8151ff 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -78,7 +78,7 @@
 
 ADD properties/ /opt/accumulo/conf/
 
-ENV HADOOP_HOME=/opt/hadoop ZOOKEEPER_HOME=/opt/zookeeper ACCUMULO_HOME=/opt/accumulo PATH="$PATH:$ACCUMULO_HOME/bin"
+ENV HADOOP_HOME=/opt/hadoop ZOOKEEPER_HOME=/opt/zookeeper ACCUMULO_HOME=/opt/accumulo PATH="$PATH:/opt/accumulo/bin"
 
 ENTRYPOINT ["accumulo"]
 CMD ["help"]