Allow creating a new Cluster with alive and down nodes

[nfo]

Scenario:

• I call hasql.NewCluster with three nodes. One node is unreachable ("context deadline exceeded").
• All further calls to Cluster.WaitFor* return an error.
• Calls to Cluster.Alive, Cluster.Primary* and Cluster.Standby* return nil.

Expected: Being able to create a cluster which includes unreachable nodes and still be able to query the alive nodes.

[vtolstov]

do you plan to fix this ?

[bbrodriges]

Yes, there will be fix soon