errorlib: fix Sentry context syntax issue

* Fixes Python syntax issue that slipped in the Sentry context support
  commit d73bd94b2fbe8666af31dfec25c334c466e6f6df.
  (addresses #1960) (PR #2147)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
BibCirculation: fix for CERN returnees

Acked-by: Tibor Simko <tibor.simko@cern.ch>
WebStat: Set default query for the custom summary

* According to RQF0382332 for CDS: Set a default query for the
  "Custom query summary" under "Administration" / "Statistics".