Fix upstream merge conflict on a900ce879b47
Merging upstream commit a900ce879b47 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 29b4f96da70a35edf61492801d99bbc3de7e25da && \
hg topic upstream-merge && \
hg merge a900ce879b47181171cd8ca748b7d50c16b10d20