[MONDRIAN-1587] Drillthrough SQL is invalid on hsqldb.
    SQL formerly included redundant parentheses in cases where drillthrough was gener
    Validated changes against postgres, greenplum, mysql, oracle, sqlserver and hsqld
    (cherry picked from commit e411d5b)
    Excludes overlapping changes for MONDRIAN-1226 from master.
Merge pull request #86 from mkambol/3.5-1587

 [MONDRIAN-1587] Drillthrough SQL is invalid on hsqldb.