CiaB: added log path of trafficops in variables.env

[Shihta]

What does this PR (Pull Request) do?

added log path of trafficops in variables.env

Which Traffic Control components are affected by this PR?

• CDN in a Box

What is the best way to verify this PR?

1. Start CiaB
2. You should get TO log by docker logs

Since there is no any new feature so I didn't provide test

If this is a bug fix, what versions of Traffic Ops are affected?

master

The following criteria are ALL met by this PR

• This PR includes tests OR I have explained why tests are unnecessary
• This PR includes documentation OR I have explained why documentation is unnecessary
• This PR includes an update to CHANGELOG.md OR such an update is not necessary
• This PR includes any and all required license headers
• This PR ensures that database migration sequence is correct OR this PR does not include a database migration
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

[asfgit]

Refer to this link for build results (access rights to CI server needed):
https://builds.apache.org/job/trafficcontrol-PR/3833/
Test PASSed.

[ocket8888]

tested by adjusting some of the values in variables.env and building/running CiaB - works as advertised.