Port offline node fixes from Rapi to IAllocator
Port offline node fixes from Rapi to IAllocator

The IAllocator source was copied from Rapi before the offline node fixes
were made. This changes such that offline nodes are accepted correctly.

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