Use only listBucket in ListingLatencyWarning
Use only listBucket in ListingLatencyWarning

Ignore getService (e.g. listing buckets), to better match requirements.

Issue: CLDSRV-83

scality/S3,scality/S3,scality/S3,scality/S3,scality/S3,scality/S3,scality/S3,scality/S3