Use /ostree/deploy as canonical API for deployment monitoring

Replaced the use of the systemd PathChanged property on
/ostree/repo/refs/heads/ostree/1/1 with /ostree/deploy, the canonical API
for monitoring deployment changes in ostree

Author: aaradhak

mantle/kola/tests/upgrade/basic.go

@@ -316,8 +316,10 @@ func runFnAndWaitForRebootIntoVersion(c cluster.TestCluster, m platform.Machine,
 func waitForUpgradeToBeStaged(c cluster.TestCluster, m platform.Machine) {
        // Here we set up a systemd path unit to watch for when ostree
        // behind the scenes updates the refs in the repo under the
-       // /ostree/repo/refs/heads/ostree/1/1 directory. refchanged.path
-       // will trigger when it gets updated and will then stop wait.service.
+       // /ostree/deploy directory.
+       // Using /ostree/deploy as the canonical API for monitoring deployment changes. 
+       // This path is updated by ostree for deployment changes.
+       // refchanged.path will trigger when it gets updated and will then stop wait.service.
        // The systemd-run --wait causes it to not return here (and thus
        // continue execution of code here) until wait.service has been
        // stopped by refchanged.service. This is an effort to make us
@@ -329,7 +331,7 @@ func waitForUpgradeToBeStaged(c cluster.TestCluster, m platform.Machine) {
        //
        // Note: if systemd-run ever gains the ability to --wait when
        //       generating a path unit then the below can be simplified.
-       c.RunCmdSync(m, "sudo systemd-run -u refchanged --path-property=PathChanged=/ostree/repo/refs/heads/ostree/1/1 systemctl stop wait.service")
+       c.RunCmdSync(m, "sudo systemd-run -u refchanged --path-property=PathChanged=/ostree/deploy systemctl stop wait.service")
        c.RunCmdSync(m, "sudo systemd-run --wait -u wait sleep infinity")
 }