Clear the warm_reset flag after boot is successful

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. After the slot has been marked as boot successful, we can drop
the warm_reset flag to avoid the performance overhead on the next
reboot.

Bug: 143489994
Test: check the property is set to 0 by vold
Change-Id: If7c922f40bcf9a6f7894af0a334ab23d88d40d17

Checkpoint.cpp

@@ -170,6 +170,10 @@ Status cp_commitChanges() {
         if (!cr.success)
             return error(EINVAL, "Error marking booted successfully: " + std::string(cr.errMsg));
         LOG(INFO) << "Marked slot as booted successfully.";
+        // Clears the warm reset flag for next reboot.
+        if (!SetProperty("ota.warm_reset", "0")) {
+            LOG(WARNING) << "Failed to reset the warm reset flag";
+        }
     }
     // Must take action for list of mounted checkpointed things here
     // To do this, we walk the list of mounted file systems.