[FIX] Properly end DB request after an error

this avoids ZODB KeyErrors after an exception
[FIX] _req in eagreement signing
[FIX] dl eagreement signed document: inline dispo
[FIX] send_file and _req usage in CFA
[FIX] send_file in SSO logout hook
[REF] Remove unused WError/WPError classes
[FIX] send_file in registrant management
[FIX] send_file and _req in sessionModif
[FIX] send_file for subcontrib marcxml
[FIX] send_file in paper reviewing
[FIX] send_file in room booking module