Fix some hscan bugs
Fix some hscan bugs

Currently hscan has a number of bugs:
  - doesn't add the common suffix (csf) to the instance's nodes
  - doesn't export the cpus for neither nodes nor instances
  - doesn't support single-node instances

This patch fixes these issues.

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