Revert "CP-7904 - Remove v6 from xe-toolstack-restart."

Put v6 back into xe-toolstack-restart now that it's back in the build.

This reverts commit a174a4346d8b907e7e792ce6b87306acf280d770.
Merge pull request #1732 from johnelse/re-add-v6d

Re-add v6d to xe-toolstack-restart