elasticsearch-river-rethinkdb has Private Subrepositories

[martinvahi]

ts2@linux-0fiz:~/tmp/xx10/demo$ ls
ts2@linux-0fiz:~/tmp/xx10/demo$ date
Wed Apr 12 10:09:57 EEST 2017
ts2@linux-0fiz:~/tmp/xx10/demo$ git clone --recursive https://github.com/rethinkdb/elasticsearch-river-rethinkdb.git
Cloning into 'elasticsearch-river-rethinkdb'...
remote: Counting objects: 247, done.
remote: Total 247 (delta 0), reused 0 (delta 0), pack-reused 247
Receiving objects: 100% (247/247), 43.56 KiB | 0 bytes/s, done.
Resolving deltas: 100% (108/108), done.
Checking connectivity... done.
Submodule 'rethink-java-driver' (git@github.com:npiv/rethink-java-driver) registered for path 'rethink-java-driver'
Cloning into 'rethink-java-driver'...
Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
Clone of 'git@github.com:npiv/rethink-java-driver' into submodule path 'rethink-java-driver' failed
ts2@linux-0fiz:~/tmp/xx10/demo$