resolve links to manpages in HTML site builder

Change-Id: Idfa64cbf16fb09bd41c0fcc88cd3a21a842b0f3f
Reviewed-on: http://review.couchbase.org/35017
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Reviewed-by: Matt Ingenthron <matt@couchbase.com>