[debian] wait for property service by socket
Created by: peat-psuwit
If using getprop alone, it can fallback to /system/build.prop, thus not ensuring the property is up. Some device (e.g. krillin) uses property service to control wifi, thus this is required.
This stems from my ueventd-as-a-udevtrigger effort which prevents double-coldbooting and fixes FP2's camera on Halium 7.1 port. However, this means the start of udev doesn't guarantee the start of Android container anymore. Thus, a better check is required.
This PR comes with Jenkinsfile update.
Related PR: https://github.com/ubports/lxc-android-config/pull/26