MT#60284 Ensure to start qemu-guest-agent only after package got installed

We install the qemu-guest-agent package in ensure_packages_installed().
Try to start the qemu-guest-agent service only afterwards therefore.

Fixup for commit 82e6638b40

Change-Id: Ic4aa2e493851b4c92ac134d68a9a76e05485658d

templates/scripts/includes/deployment.sh

@@ -1533,12 +1533,6 @@ trap 'wait_exit;' 1 2 3 6 15 ERR EXIT
 echo "Host IP: $(ip-screen)"
 echo "Deployment version: $SCRIPT_VERSION"
 
-# MT#60284 ensure qemu-guest-agent is running if it's available in VM
-if [ -e /dev/virtio-ports/org.qemu.guest_agent.0 ] ; then
-  echo "Guest Agent VirtIO device detected, starting qemu-guest-agent service"
-  systemctl start qemu-guest-agent
-fi
-
 enable_deploy_status_server
 
 set_deploy_status "checkBootParam"
@@ -1826,6 +1820,12 @@ fi
 
 ensure_packages_installed
 
+# MT#60284 ensure qemu-guest-agent is running if it's available in VM
+if [ -e /dev/virtio-ports/org.qemu.guest_agent.0 ] ; then
+  echo "Guest Agent VirtIO device detected, starting qemu-guest-agent service"
+  systemctl start qemu-guest-agent
+fi
+
 # this is important for "buster", do not update the string for "bullseye" or
 # future releases
 case "${DEBIAN_RELEASE}" in