We can't (and don't need to) repeatedly get the $each_smsg
callback for each URI since that clobbers {ovv_buf} before
it can be output.
I initially thought this was a dedupe-related bug and
moved the dedupe code into the $each_smsg callback to
minimize differences. Nevertheless it's a nice code
reduction.
I also thought it was related to incomplete smsg info,
so {references} is now filled in correctly for dedupe.