Better logging for generic record

Change-Id: I6840881c51c073b527f38e74703c0a0364051bc6
Reviewed-on: https://asterix-gerrit.ics.uci.edu/927
Reviewed-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Till Westmann <tillw@apache.org>
diff --git a/asterixdb/asterix-external-data/src/main/java/org/apache/asterix/external/input/record/GenericRecord.java b/asterixdb/asterix-external-data/src/main/java/org/apache/asterix/external/input/record/GenericRecord.java
index f405b82..06386ba 100644
--- a/asterixdb/asterix-external-data/src/main/java/org/apache/asterix/external/input/record/GenericRecord.java
+++ b/asterixdb/asterix-external-data/src/main/java/org/apache/asterix/external/input/record/GenericRecord.java
@@ -54,4 +54,9 @@
     @Override
     public void reset() {
     }
+
+    @Override
+    public String toString() {
+        return record == null ? null : record.toString();
+    }
 }