WebSearch: correct record sums from hosted colls

* The number of records in a collections (nbrecs) is now correctly calculated
  including records coming from descendant hosted collections.  (closes #1651)

Reported-by: Theodoropoulos Theodoros <theod@lib.auth.gr>
Signed-off-by: Nikolaos Kasioumis <nikolaos.kasioumis@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>