Remove unused imports

Author: charlesmyu

dd-java-agent/instrumentation/spark/src/main/java/datadog/trace/instrumentation/spark/SparkSQLUtils.java

@@ -17,14 +17,10 @@
 import org.apache.spark.scheduler.AccumulableInfo;
 import org.apache.spark.sql.execution.SparkPlanInfo;
 import org.apache.spark.sql.execution.metric.SQLMetricInfo;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import scala.Tuple2;
 import scala.collection.JavaConverters;
 
 public class SparkSQLUtils {
-  private static final Logger log = LoggerFactory.getLogger(SparkSQLUtils.class);
-
   public static void addSQLPlanToStageSpan(
       AgentSpan span,
       SparkPlanInfo plan,