log sqs messages at 'debug' rather than 'info' level
log sqs messages at 'debug' rather than 'info' level

Fixes #2790.

alban/scope,kinvolk/scope,alban/scope,kinvolk/scope,kinvolk/scope,weaveworks/scope,alban/scope,weaveworks/scope,weaveworks/scope,kinvolk/scope,kinvolk/scope,alban/scope,kinvolk/scope,weaveworks/scope,alban/scope,alban/scope,weaveworks/scope,weaveworks/scope