Incorrect variable TMT_PLANS_DATA used in tmt plans

[psss]

The TMT_PLANS_DATA environment variable is used across the tmt plans to point to a directory where git clone is supposed to fetch the repository. The correct name is TMT_PLAN_DATA so the variable is expanded into an empty string and the git repo is stored into the root directory. Here's a recent job confirming this:

Cloning into '/ci-dnf-stack'...

I would not recommend using TMT_PLAN_DATA as this is intended for storing interesting information which should be fetched from the guest and should be kept among test artifacts.

Path to the common directory used for storing logs and other
artifacts related to the whole plan execution. It is pulled
back from the guest and available for inspection after the
plan is completed.

I guess you could just use /tmp for this use case?