do not redefine path in elasticsearch

in I0272d56bc2e50e8174db78bd449f65f60f7f4000, we reset DEST value
when installing elasticsearch. it gets set to /opt/stack/ which is
not always correct in gate causing the path to be wrong and
elasticseach cannot be installed. we should reuse DEST from stackrc

Change-Id: Ia3a2383ada30c4e92c37386aedd6164c69cac60a
Closes-Bug: #1484182
diff --git a/pkg/elasticsearch.sh b/pkg/elasticsearch.sh
index 79f67a0..14d13cf 100755
--- a/pkg/elasticsearch.sh
+++ b/pkg/elasticsearch.sh
@@ -6,9 +6,7 @@
 # step can probably be factored out to something nicer
 TOP_DIR=$(cd $(dirname "$0")/.. && pwd)
 FILES=$TOP_DIR/files
-source $TOP_DIR/functions
-DEST=${DEST:-/opt/stack}
-source $TOP_DIR/lib/infra
+source $TOP_DIR/stackrc
 
 # Package source and version, all pkg files are expected to have
 # something like this, as well as a way to override them.