QA: Fix CheckFileUnmodified to work with vcluster
QA: Fix CheckFileUnmodified to work with vcluster

Signed-off-by: Petr Pudlak <9d19625f8ee825a2c398462ed335cbcf98f79c32@google.com>
Reviewed-by: Hrvoje Ribicic <be5828fca31f89218048bec4189e30a581aa65da@google.com>

onponomarev/ganeti,bitemyapp/ganeti,leshchevds/ganeti,ganeti/ganeti,onponomarev/ganeti,yiannist/ganeti,mbakke/ganeti,mbakke/ganeti,dimara/ganeti,grnet/snf-ganeti,dimara/ganeti,leshchevds/ganeti,andir/ganeti,andir/ganeti,yiannist/ganeti,leshchevds/ganeti,ganeti/ganeti,mbakke/ganeti,yiannist/ganeti,andir/ganeti,grnet/snf-ganeti,ganeti/ganeti,bitemyapp/ganeti