cassandra: better handling of corrupted metrics
cassandra: better handling of corrupted metrics

Thib17/biggraphite,iksaif/biggraphite,criteo/biggraphite,iksaif/biggraphite,criteo/biggraphite,Thib17/biggraphite,Thib17/biggraphite,criteo/biggraphite,iksaif/biggraphite,criteo/biggraphite,iksaif/biggraphite,Thib17/biggraphite