Remove hadoop dependency in DatumFactory

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/io/RawComparator
at org.apache.tajo.datum.DatumFactory.createFromBytes(DatumFactory.java:124)
at org.apache.tajo.catalog.statistics.ColumnStats.<init>(ColumnStats.java:59)
at org.apache.tajo.catalog.statistics.TableStats.<init>(TableStats.java:91)
at org.apache.tajo.catalog.TableDesc.<init>(TableDesc.java:73)
at org.apache.tajo.catalog.CatalogUtil.newTableDesc(CatalogUtil.java:338)
at org.apache.tajo.jdbc.WaitingResultSet.waitOnResult(WaitingResultSet.java:65)
at org.apache.tajo.jdbc.WaitingResultSet.getSchema(WaitingResultSet.java:52)
at org.apache.tajo.jdbc.TajoStatement.executeSQL(TajoStatement.java:167)
at org.apache.tajo.jdbc.TajoPreparedStatement.executeImmediate(TajoPreparedStatement.java:92)
at org.apache.tajo.jdbc.TajoPreparedStatement.executeQuery(TajoPreparedStatement.java:76)
at org.apache.tajo.jdbc.TestJdbc.main(TestJdbc.java:31)
Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.io.RawComparator
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)