Schedule a warm_reset after an OTA

The property is set to inform kernel to do a warm_reset on the next
reboot. This is useful to persist the logs to debug device boot
failures. More details in http://go/rvc-ota-persist-logs.

Bug: 143489994
Test: check the property sets after an update
Change-Id: I776a6996e3b3ef77514da0acc91585d28e5cdf15
diff --git a/hardware_chromeos.cc b/hardware_chromeos.cc
index 8ef05b2..a49375e 100644
--- a/hardware_chromeos.cc
+++ b/hardware_chromeos.cc
@@ -333,4 +333,6 @@
   return true;
 }
 
+void HardwareChromeOS::SetWarmReset(bool warm_reset) {}
+
 }  // namespace chromeos_update_engine