• Dangling indices are not imported if a tombstone for the same index

    (same name and UUID) exists in the cluster state.  This resolves a
    situation where if an index data folder was copied into a node's data
    directory while the node is running and that index had a tombstone in
    the cluster state, the index would still get imported.
    
    Closes elastic#18250
    Closes elastic#18249
    Ali Beyad
    Ali Beyad committed May 11, 2016