util: eliminate the possibility of returning None from `versiontuple()`
This fixes the following error flagged by pytype:
File "/mnt/c/Users/Matt/hg/mercurial/extensions.py", line 228, in load: unsupported operand types for > [unsupported-operands]
Primitive types 'Optional[tuple]' and 'curver: Optional[tuple]' are not comparable.
Differential Revision: https://phab.mercurial-scm.org/D11473
# Balto (https://bitbucket.org/lothiraldan/balto/src) is a test orchestrator
# which is compatible with all test runner that can emit the LITF
# (https://github.com/lothiraldan/litf) test format.
# The plugin for the Mercurial test runner is mercurial-litf
# (https://pypi.org/project/mercurial-litf/). Make sure to follow the
# instruction and configuration instructions here:
# https://bitbucket.org/lothiraldan/mercurial_litf/src/default/
# You can launch Balto with `balto /path/to/mercurial/tests/`
name = "Mercurial Test Suite"
tool = "mercurial"