Add no postinstall option am: bec0f07516 am: 33c2435597 am: df3a22e54b

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/1660742

Change-Id: I80bfc439cc92f13c771ec651748646c5eaa7961d
diff --git a/scripts/update_device.py b/scripts/update_device.py
index 074b91d..b784b1b 100755
--- a/scripts/update_device.py
+++ b/scripts/update_device.py
@@ -428,6 +428,8 @@
                       help='Update with the secondary payload in the package.')
   parser.add_argument('--no-slot-switch', action='store_true',
                       help='Do not perform slot switch after the update.')
+  parser.add_argument('--no-postinstall', action='store_true',
+                      help='Do not execute postinstall scripts after the update.')
   parser.add_argument('--allocate_only', action='store_true',
                       help='Allocate space for this OTA, instead of actually \
                         applying the OTA.')
@@ -472,6 +474,8 @@
 
   if args.no_slot_switch:
     args.extra_headers += "\nSWITCH_SLOT_ON_REBOOT=0"
+  if args.no_postinstall:
+    args.extra_headers += "\nRUN_POST_INSTALL=0"
 
   with zipfile.ZipFile(args.otafile) as zfp:
     CARE_MAP_ENTRY_NAME = "care_map.pb"