[autotest] Redesign how host history is queried to avoid any DB access

The host list is retrieved from metaDB for given board and label.

BUG=chromium:419043
TEST=local run
host_history.py --board peppy -l 240
host_history.py -l 240 --hosts 172.27.213.193

Change-Id: I63595534f167b1676f62e03e0c1643479e1e1f12
Reviewed-on: https://chromium-review.googlesource.com/221743
Tested-by: Dan Shi <dshi@chromium.org>
Reviewed-by: Fang Deng <fdeng@chromium.org>
Commit-Queue: Dan Shi <dshi@chromium.org>
diff --git a/site_utils/host_label_utils.py b/site_utils/host_label_utils.py
index f408a8a..2209383 100755
--- a/site_utils/host_label_utils.py
+++ b/site_utils/host_label_utils.py
@@ -8,9 +8,9 @@
 This script provides functions to:
 1. collect: Collect all hosts and their labels to metaDB, can be scheduled
             run daily, e.g.,
-            ./site_utils/host_labels_utils.py collect
+            ./site_utils/host_label_utils.py collect
 2. query: Query for hosts and their labels information at a given day, e.g.,
-          ./site_utils/host_labels_utils.py query -n 172.27.213.193 -l peppy
+          ./site_utils/host_label_utils.py query -n 172.27.213.193 -l peppy
 """
 
 import argparse