At the moment, Subversion's trunk and 1.8.x branch code SEGFAULT when trying to
show a repos diff of a revision in which an empty file was added.
This is caused by a change made in r1470994, where the repository diff code was
changed to lazily open tempfile streams. The lazy open bit is good (and greatly
reduces the number of file handles held open during a repository diff via
ra-serf), but we need to ensure that those stream do, in fact, get eventually
opened. Currently, empty added files passed through the system will not every
trigger the lazy open logic.