Description
Currently one can only use AutoAddReplicas with HdfsDirectoryFactory.
I should also be able to use any directory factory as long as my underlying filesystem is shared. I could be using MMapDirectory factory and have an underlying NFS shared Filesystem.
We should make the 'isSharedStorage' param configurable in solrconfig. This should be set to true by the user if their underlying FS is shared. Currently 'isSharedStorage' is hardcoded to true for HDFSDir.