Text Backend: correctly read data for offline nodes
Text Backend: correctly read data for offline nodes

With standby nodes, simply ignoring the specification of
an offline node is not sufficient any more.

Signed-off-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>
Reviewed-by: Helga Velroyen <2d0126b1ec6f9ec5cbec4a7012aa14faeaef10f5@google.com>

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