Switch config.py to logging
Switch config.py to logging

A couple of more modules are using the obsolete logger functions, config
being one of them.

Reviewed-by: imsnah

yiannist/ganeti,apyrgio/ganeti,dimara/ganeti,ganeti/ganeti,yiannist/ganeti,bitemyapp/ganeti,apyrgio/ganeti,ganeti/ganeti,mbakke/ganeti,leshchevds/ganeti,ganeti-github-testing/ganeti-test-1,mbakke/ganeti,apyrgio/snf-ganeti,onponomarev/ganeti,bitemyapp/ganeti,grnet/snf-ganeti,mbakke/ganeti,yiannist/ganeti,andir/ganeti,andir/ganeti,ganeti/ganeti,ganeti-github-testing/ganeti-test-1,leshchevds/ganeti,andir/ganeti,dimara/ganeti,leshchevds/ganeti,onponomarev/ganeti,grnet/snf-ganeti,apyrgio/snf-ganeti