Fix group() query logging so it uses 'key' instead of 'keys'
Fix group() query logging so it uses 'key' instead of 'keys'

tomasbro/DoctrineMongoDBBundle,Soullivaneuh/DoctrineMongoDBBundle,castarco/DoctrineMongoDBBundle,juchi/DoctrineMongoDBBundle,0mars/DoctrineMongoDBBundle,malarzm/DoctrineMongoDBBundle,Soullivaneuh/DoctrineMongoDBBundle,juchi/DoctrineMongoDBBundle,castarco/DoctrineMongoDBBundle,tomasbro/DoctrineMongoDBBundle,jahller/DoctrineMongoDBBundle,alcaeus/DoctrineMongoDBBundle,jahller/DoctrineMongoDBBundle,doctrine/DoctrineMongoDBBundle,sarcher/DoctrineMongoDBBundle,stof/DoctrineMongoDBBundle,0mars/DoctrineMongoDBBundle,malarzm/DoctrineMongoDBBundle,alcaeus/DoctrineMongoDBBundle