Integrate reply_part_content function into reply_part function.

Integrate reply_part_content function into reply_part function.

After the last patch to eliminate some redundant code paths in
reply_part, the reply_part_content function was only being called
once.  Disolving the function and integrating its contents into the
reply_part function makes things a little simpler, and frees up some
name space that will be needed in the next patch.