After upgrade HBase lib (in scope of
DRILL-6349) in Drill project sources root directory the extraneous directory can be created in the process of mvn clean install -DskipTests -pl contrib/storage-hbase/
It is related to absent maven-metadata.xml file in org.glassfish:javax.el transitive dependency from HBase lib.
See info from mvn release:prepare -X:
So it can be easily reproduced with removing org.glassfish:javax.el from local maven repo:
and making Drill build for HBase package:
Solution: update HBase lib to the latest 2.1.1 version, since
HBASE-21005 resolved there.