memcached and other processes fail to start if analytics directory not writable upon restart

During some testing with Alice I had setup a single node on an AWS instance.  This instance was then stopped (paused/hibernated) and when it restarted, ns_server was able to start back up but the node did not come online.  Initial review showed that the memcached process was not started and was not even trying be started.  A bit further review showed actually that many processes were not being started by the babysitter but it was not clear why.

I was able to reproduce this a second time with 6.0 build 1360 and logs are here: https://s3.amazonaws.com/cb-engineering/perry/failed_to_start/collectinfo-2018-07-24T151740-ns_1%40ec2-52-40-48-173.us-west-2.compute.amazonaws.com.zip