Fix access to uninitialized values in QtXmlPatterns

Fixes valgrind warning like below when executing tst_QXmlQuery::copyConstructor()
  Conditional jump or move depends on uninitialised value(s)
    at: QPatternist::NodeIndexStorage::operator!=(QPatternist::NodeIndexStorage const&) const (q
    by: QXmlItem::operator=(QXmlItem const&) (qabstractxmlnodemodel.cpp:1228)

Reason for the warning is that QPatternist::NodeIndexStorage::operator!=
accesses all fields of NodeIndexStorage, which are all not intialized in
every execution path of QXmlItem::QXmlItem(const QVariant &) and class
QPatternist::Item constructors.

Fixed by adding NodeIndexStorage::reset() function that resets all fields
and put a call to that function where NodeIndexStorage objects were
previously incompletely initialized. Note that unfortunately class
NodeIndexStorage cannot have a default constructor, because it is used as
a union field.

Change-Id: I686433ba552f025658f7e583226e77346db82159
(cherry picked from commit f42f82f435d738339ad85c1380d1167338517247)
(cherry picked from commit 65d2458408ccda1b37e1069fd13791a60fa0c672)
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>

0 files changed, 0 insertions, 0 deletions