Fix "os" import in wallet-dump.py
Fix "os" import in wallet-dump.py

This is now needed as we don't use "from test_framework.util import *" anymore.

dashpay/dash,UdjinM6/dash,nmarley/dash,ionomy/ion,ionomy/ion,nmarley/dash,nmarley/dash,nmarley/dash,dashpay/dash,UdjinM6/dash,thelazier/dash,UdjinM6/dash,UdjinM6/dash,nmarley/dash,ionomy/ion,nmarley/dash,dashpay/dash,dashpay/dash,ionomy/ion,thelazier/dash,nmarley/dash,thelazier/dash,dashpay/dash,UdjinM6/dash,thelazier/dash,ionomy/ion,thelazier/dash,ionomy/ion