It is something Avast has to do. I emailed alienman tech and he is doing what he can to fix the problem. Several antivirus/malware apps fix their issue with this. I am getting very annoyed with the PUP message also.

Message in play store:
** Antivirus warnings **
If you have an antivirus app that is reporting Where’s My Droid as a virus you may need to update your antivirus app. We contacted many app developers about this false report and many have fixed it in recent updates.