Use a plugin setting for key

run

@@ -4,6 +4,6 @@ TARGET=$PLUGIN_TARGET
 
 mkdir /tmp/deploy
 cp -Rv $SOURCE /tmp/deploy
-echo "$DEPLOY_KEY" > /tmp/deploy.rsa
+echo "$PLUGIN_KEY" > /tmp/deploy.rsa
 chmod 0600 /tmp/deploy.rsa
 scp -i /tmp/deploy.rsa -o StrictHostKeyChecking=no -r /tmp/deploy/* $TARGET