Add optional SAS logging for memcached - if the trail ID argument is not given, it shouldn't log (because we're not doing this in Sprout yet)
Correct default values
Merge pull request #76 from Metaswitch/memcached_sas_trace

[Reviewer: Graeme] Add optional SAS logging for memcached - if the trail ID argument is not...
Merge remote-tracking branch 'origin/sas_integration' into ralf_events
Merge pull request #78 from Metaswitch/ralf_events

[Reviewer: Graeme] Ralf events