correct installation instructions

1 job for master in 2 minutes and 23 seconds (queued for 2 seconds)
Status Name Job ID Coverage
failed master_deploy #17967


Name Stage Failure
master_deploy Test There is an unknown failure, please try again
[2017-07-24T15:24:02Z] WARNING: Nikola: Make sure to use an UTF-8 locale to ensure Unicode support.
Scanning posts...done!
[2017-07-24T15:24:03Z] INFO: deploy: => preset 'default'
[2017-07-24T15:24:03Z] INFO: deploy: ==> rsync -rlv -e 'ssh -i deploy_key' --delete --filter 'P doc/*' output/*
ssh: connect to host port 22: Network is unreachable
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(226) [sender=3.1.1]
[2017-07-24T15:26:10Z] ERROR: deploy: Failed deployment -- command rsync -rlv -e 'ssh -i deploy_key' --delete --filter 'P doc/*' output/* returned 255
ERROR: Job failed: exit code 1