juno boot time: update to use tag "juno-reference"

so that we avoid the queue when juno-01 is offline.

Change-Id: Iccac569e80251956b3cef425a61e63c2d6a101ac
Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
diff --git a/android/lcr-member-juno-m/template-boottime.json b/android/lcr-member-juno-m/template-boottime.json
index 9858daa..2ae8146 100644
--- a/android/lcr-member-juno-m/template-boottime.json
+++ b/android/lcr-member-juno-m/template-boottime.json
@@ -220,7 +220,8 @@
             }
         }
     ],
-    "target": "juno-01",
+    "device_type": "juno",
+    "tags": [ "juno-reference" ],
     "image_type": "android",
     "priority": "high",
     "job_name": "%%JOB_NAME%%-%%ANDROID_META_BUILD%%-boottime",