tgtd.service: Wait for tgtd to be ready

If we don't wait, it fails with:
  tgtadm: failed to send request hdr to tgt daemon, Transport endpoint is
  not connected

It's not a pretty solution but CentOS and Fedora do the same workaround.

scripts/tgtd.service

@@ -9,6 +9,9 @@ ConditionPathExists=/etc/tgt/targets.conf
 Environment=TGTD_CONFIG=/etc/tgt/targets.conf
 
 ExecStart=/usr/sbin/tgtd --foreground
+# Wait for tgtd to be ready
+# See https://bugzilla.redhat.com/show_bug.cgi?id=848942
+ExecStartPost=/usr/sbin/sleep 5
 ExecStartPost=/usr/sbin/tgtadm --op update --mode sys --name State -value offline
 ExecStartPost=/usr/sbin/tgtadm --op update --mode sys --name State -value ready
 ExecStartPost=/usr/sbin/tgt-admin --verbose --execute --conf ${TGTD_CONFIG}