autotest: Increate count of pings for ServoHost

In case if one ping will fail is better to try a few times

BUG=None
TEST=run local repair

Change-Id: I38b71cd800cbae45df89b69181a4e71a86f89011
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/2580128
Commit-Queue: Garry Wang <xianuowang@chromium.org>
Reviewed-by: Garry Wang <xianuowang@chromium.org>
Tested-by: Otabek Kasimov <otabek@google.com>
Auto-Submit: Otabek Kasimov <otabek@google.com>
diff --git a/server/hosts/servo_host.py b/server/hosts/servo_host.py
index 437a5ab..c6e5de6 100644
--- a/server/hosts/servo_host.py
+++ b/server/hosts/servo_host.py
@@ -1686,7 +1686,7 @@
         return None, servo_constants.SERVO_STATE_NO_SSH
 
     newhost = ServoHost(**servo_args)
-    if not newhost.is_up_fast():
+    if not newhost.is_up_fast(count=3):
         # We do not have any option to recover servo_host.
         # If servo_host is not pingable then we can stop here.
         return None, servo_constants.SERVO_STATE_NO_SSH