Don't assume that all log entries have a .req member
Don't assume that all log entries have a .req member

The cassandra backend log messages in particular (emitted on startup for
example) don't have a 'req' entry associated with them. Don't crash in that
situation.

Krenair/restbase,wikimedia/restbase,eevans/restbase,milimetric/restbase,physikerwelt/restbase,Pchelolo/restbase,wikimedia/mediawiki-services-restbase,wikimedia/restbase,wikimedia/mediawiki-services-restbase,cscott/restbase,d00rman/restbase,gwicke/restbase,inverno/restbase,Pchelolo/restbase,eevans/restbase,gwicke/restbase,physikerwelt/restbase,wikimedia/hyperswitch,inverno/restbase,cscott/restbase,Krenair/restbase,d00rman/restbase,milimetric/restbase