core: print the stdout on errors

If we fail fetching the ceph version let's also print the stdout since
ceph tends to put the error here too.

Signed-off-by: Sébastien Han <seb@redhat.com>

pkg/daemon/ceph/client/upgrade.go

@@ -46,7 +46,7 @@ func getCephMonVersionString(context *clusterd.Context, clusterInfo *ClusterInfo
 	args := []string{"version"}
 	buf, err := NewCephCommand(context, clusterInfo, args).Run()
 	if err != nil {
-		return "", errors.Wrap(err, "failed to run 'ceph version'")
+		return "", errors.Wrapf(err, "failed to run 'ceph version'. %s", string(buf))
 	}
 	output := string(buf)
 	logger.Debug(output)