Solved a bug introduced in DNode listener

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
# En la rama master
# Your branch is up-to-date with 'origin/master'.
#
# Cambios para hacer commit:
#	modificado: splout-hadoop/src/main/java/com/splout/db/hadoop/SchemaSampler.java
#
# Archivos sin seguimiento:
#	CHANGES.txt~
#	README.md~
#	out-com.splout.db.hadoop.TestTablespaceGenerator/
#	out-com.splout.db.hadoop.TestTablespaceGeneratorJavaScript/
#	splout-hadoop/.in-com.splout.db.hadoop.TestTablespaceGeneratorJavaScript.crc
#	splout-hadoop/.input-com.splout.db.hadoop.TestTupleSampler_1.crc
#	splout-hadoop/.input-com.splout.db.hadoop.TestTupleSampler_2.crc
#	splout-hadoop/.input-com.splout.db.hadoop.TestTupleSampler_3.crc
#	splout-hadoop/.input-com.splout.db.hadoop.TestTupleSampler_r.crc
#	splout-hadoop/.output-com.splout.db.hadoop.TestTupleSampler_1.crc
#	splout-hadoop/.output-com.splout.db.hadoop.TestTupleSampler_2.crc
#	splout-hadoop/.output-com.splout.db.hadoop.TestTupleSampler_3.crc
#	splout-hadoop/.output-com.splout.db.hadoop.TestTupleSampler_r.crc
#	splout-hadoop/database-files/
#	splout-hadoop/ddate.json
#	splout-hadoop/derby.log
#	splout-hadoop/idadvertiser.json
#	splout-hadoop/idpublisher.json
#	splout-hadoop/metastore_db/
#	splout-hadoop/pangool-instances/
#	splout-hadoop/src/main/java/com/splout/db/benchmark/TablespaceAnalyserCMD.java
#	splout-server/dnode-staging-0/
#	splout-server/dnode-staging-1/
#	splout-server/dnode-staging-2/
#	splout-server/hz-data/
#