DERBY-5972 -  Grammar doesn't accept OR operator without parentheses

backport 1408136 from trunk to 10.8
Contributed by Knut Anders Hatlen



git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/branches/10.8@1509375 13f79535-47bb-0310-9956-ffa450edef68