Previous patch (revision 1185) for the comments-related segfault was incomplete,...

Previous patch (revision 1185) for the comments-related segfault was incomplete, and as such, it broke keywords in files whose metadata had keywords but no comments.

This patch fixes that (and still fixes the case where one searches on
comments and hits a file with keywords but no comments).  Lastly, I would
imagine that there exists a failure mode where one searches for a keyword and
hits a file with a comment but no keyword, and I imagine this patch should fix
that case as well.

Patch by Omari Stephens (aka xsdg).