BibUpload: matching existing records

• Upon insertion, bibupload automatically tries to match existing record (e.g. by OAI ID, or DOI). Deleted records should not be considered as candidates for matching. This commit assures no deleted record is matched upon insertion. (closes #1438)

• Note: this implementation is triggered only in case CFG_INSPIRE_SITE=1 or CFG_CERN_SITE=1. The appropriate implementation should be rather based on correct usage of pidstore.

Signed-off-by: Samuele Kaplun <samuele.kaplun@cern.ch>