Hi,

Whilst working on the Reproducible Builds effort [0], we noticed that
tea-cli could not be built reproducibly.

This is because the generation of BUILD_DATE in debian/rules (which ends
up in a manpage) took into account the surrounding timezone which, of
course, can vary.

Patch attached that ensures that BUILD_DATE is always generated in the
"UTC" timezone.

 [0] https://reproducible-builds.org/


Regards,