Adding support for quiescent reboot to recovery

Bug: 37401320
Test: build and push OTA and hit adb reboot recovery,quiescent. The screen should remain off throughout the upgrade process.
Change-Id: Ibed3795c09e26c4fa73684d40b94e40c78394d3f
diff --git a/updater/install.cpp b/updater/install.cpp
index 857d7f1..888239c 100644
--- a/updater/install.cpp
+++ b/updater/install.cpp
@@ -890,7 +890,10 @@
     return StringValue("");
   }
 
-  const std::string reboot_cmd = "reboot," + property;
+  std::string reboot_cmd = "reboot," + property;
+  if (android::base::GetBoolProperty("ro.boot.quiescent", false)) {
+    reboot_cmd += ",quiescent";
+  }
   android::base::SetProperty(ANDROID_RB_PROPERTY, reboot_cmd);
 
   sleep(5);