Fix problem with record's count

[vkuznet]

RIght now to get total number of results I invoke the count, since I added empty records to protect access of services which does not return results, I should exclude them from the count of results for given query. Should be trivial, e.g.
db.merge.find(spec)count()
where spec contains query and non-existance of 'das.empty_record'.

[vkuznet]

valya: (In 41f5232) DAS web enhancements: fixes #525, #542, #455.

Signed-off-by: Valentin Kuznetsov vkuznet@gmail.com