flake8
passed.
JSHint
passed.
Check for hg executable only if needed
Review Request #9708 — Created Feb. 28, 2018 and submitted
If a Review Board instance uses hgweb only
it is not necessary to have a hg exeutable
on that system.
Removed hg executable from system and saw that
a diff can be shown und a new review request
could be opened by post-commit /r/new/
