SimilarityIndex: Correct comment explaining the logic

This comment was wrong, due to a copy-and-paste error.  Here the
code is looking at records of dst that do not exist in src, and
are skipping past them to find another match.

Change-Id: I07c1fba7dee093a1eeffcf7e0c7ec85446777ffb
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
1 file changed