Non-root lucene index throws exception if query constraints match root of sub-tree

LucenePropetyIndexProvider returns incorrect (normalized) path for root of sub-tree if index is defined on the sub-tree. e.g.
/jcr:root/test//element(*, nt:base)[@foo='bar'] would fail with following defn

+ /test
    - foo="bar"
    + test1
          - foo="bar"
    + oak:index
           - indexRules/nt:base/properties/foo/propertyIndex="true"