Fix upstream merge conflict on 29a5559f0a8a
Merging upstream commit 29a5559f0a8a gives a conflict.
A human being has to perform merge and resolution for the automatic merge process to resume.
Command for clean conflict reproduction:
hg pull
hg --config command.update.check=abort update heptapod && \
hg topic upstream-merge && \
hg merge 29a5559f0a8a7238a6a8716bfe37dd6657726950