buildbot failure in Mercurial on hg tests

[hgbuildbot at kublai.com]

The Buildbot has detected a new failure on builder hg tests while building hg.
Full details are available at:
 http://hgbuildbot.kublai.com/builders/hg%20tests/builds/154

Buildbot URL: http://hgbuildbot.kublai.com/

Buildslave for this Build: l6

Build Reason: scheduler
Build Source Stamp: [branch default] 21e18c608b68e0c10c8a327537f9ceadbc8c3219
Blamelist: Adrian Buehlmann <adrian at cadifra.com>,Matt Harbison <matt_harbison at yahoo.com>,Nikolaj Sjujskij <sterkrig at myopera.com>,Pierre-Yves David <pierre-yves.david at ens-lyon.org>

BUILD FAILED: failed http2

sincerely,
 -The Buildbot