minor bugs

[rendicott]

Better error handling for bad access keys
handle missing token section in config

[jeffarredondo]

Not a big deal, but I ran into an issue when getting creds for >200 accounts. Maybe it needs some throttling

t=2020-03-17T16:42:52-0400 lvl=info msg="got result of assumption" message= error="RequestError: send request failed\ncaused by: Post https://sts.amazonaws.com/: dial tcp: lookup sts.amazonaws.com on 192.168.86.1:53: dial udp 192.168.86.1:53: socket: too many open files" profileName=redacted