etcd: implement separate system tests

- add t13_etcd test directory
- etcd will be started for the unit tests and each system test
- etcd will load fixture DB export if requested by the test
- existing tests are reused for etcd testing

system/t13_etcd/start-etcd.sh

@@ -0,0 +1,23 @@
+#!/bin/sh
+
+if [ -e /tmp/etcd.pid ]; then
+    echo etcd already running, killing..
+    etcdpid=`cat /tmp/etcd.pid`
+    kill $etcdpid
+    sleep 2
+fi
+
+finish()
+{
+    if [ -n "$etcdpid" ]; then
+        echo terminating etcd
+        kill $etcdpid
+    fi
+}
+trap finish INT
+
+/srv/etcd/etcd --max-request-bytes '1073741824' --data-dir /tmp/etcd-data &
+echo $! > /tmp/etcd.pid
+etcdpid=`cat /tmp/etcd.pid`
+wait $etcdpid
+echo etcd terminated