Fix failing unit test in Pherf

estColumnRulesApplied(org.apache.phoenix.pherf.DataIngestIT) Time elapsed: 3.567 sec <<< ERROR!
java.sql.SQLException: ERROR 1010 (42M01): Not allowed to mutate table. tableName=PHERF.TEST_MULTI_TENANT_TABLE
at org.apache.phoenix.exception.SQLExceptionCode$Factory$1.newException(SQLExceptionCode.java:389)
at org.apache.phoenix.exception.SQLExceptionInfo.buildException(SQLExceptionInfo.java:145)
at org.apache.phoenix.schema.MetaDataClient.dropTable(MetaDataClient.java:2130)
at org.apache.phoenix.schema.MetaDataClient.dropTable(MetaDataClient.java:2043)
at org.apache.phoenix.jdbc.PhoenixStatement$ExecutableDropTableStatement$1.execute(PhoenixStatement.java:873)
at org.apache.phoenix.jdbc.PhoenixStatement$2.call(PhoenixStatement.java:315)
at org.apache.phoenix.jdbc.PhoenixStatement$2.call(PhoenixStatement.java:307)
at org.apache.phoenix.call.CallRunner.run(CallRunner.java:53)
at org.apache.phoenix.jdbc.PhoenixStatement.executeMutation(PhoenixStatement.java:305)
at org.apache.phoenix.jdbc.PhoenixStatement.executeUpdate(PhoenixStatement.java:1364)