tsh logout deletes the profile link

[kontsevoy]

Introduction

tsh login --proxy=a would create a profile file for the proxy a and save it as ~/.tsh/a.yaml. The idea here is that a user can edit that file to avoid typing CLI flags in the future. In other words, if a profile exists I should be able to simply:

$ tsh login

... and it should pick up the proxy server parameters from a profile file.

Problem

tsh logout currently deletes the ~/.tsh/profile symlink, i.e. you MUST type the full-spec login command again, partially defeating the purpose of having profile files.

Example

Here's how it's supposed to work:

# login into proxy.example.com with custom ports 32,31 and 11 and select cluster-2
$ tsh login --proxy=proxy.example.com:32,31,11 cluster-2

# remove my certs from ~/.tsh/keys and ssh-agent
$ tsh logout

# Same as tsh login --proxy=proxy.example.com:32,31,11 cluster-2
$ tsh login