Comment 1 for bug 1158975

The second query is a bug in the optimizer, see stack below. I'm assigning this to Markos while I'm still working on the first query.

==6659== Memcheck, a memory error detector
==6659== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al.
==6659== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info
==6659== Command: ./zorba/build/bin/zorba -f -q e.xq
==6659==
==6659== Invalid read of size 8
==6659== at 0x56F2FA4: zorba::store::Item::isError() const (item.h:177)
==6659== by 0x56F1368: zorba::execute(zorba::CompilerCB*, zorba::expr*, zorba::store::ItemHandle<zorba::store::Item>&) (fold_rules.cpp:483)
==6659== by 0x56F0FEB: zorba::FoldConst::apply(zorba::RewriterContext&, zorba::expr*, bool&) (fold_rules.cpp:408)
==6659== by 0x56DB24D: zorba::RuleMajorDriver::rewrite(zorba::RewriterContext&) (rule_driver.cpp:63)
==6659== by 0x56DC85E: zorba::DefaultOptimizer::rewrite(zorba::RewriterContext&) (default_optimizer.cpp:95)
==6659== by 0x57190E9: zorba::XQueryCompiler::optimize(zorba::expr*) (compiler_api.cpp:375)
==6659== by 0x5718D2B: zorba::XQueryCompiler::compile(zorba::rchandle<zorba::parsenode> const&, bool, unsigned long&, zorba::audit::ScopedRecord&) (compiler_api.cpp:275)
==6659== by 0x5718BAB: zorba::XQueryCompiler::compile(std::istream&, zorba::rstring<zorba::rstring_classes::rep<zorba::atomic_int, std::char_traits<char>, std::allocator<char> > > const&, unsigned long&) (compiler_api.cpp:241)
==6659== by 0x549A4E2: zorba::XQueryImpl::doCompile(std::istream&, Zorba_CompilerHints const&, bool, unsigned long&) (xqueryimpl.cpp:611)
==6659== by 0x549A054: zorba::XQueryImpl::compile(std::istream&, zorba::SmartPtr<zorba::StaticContext> const&, Zorba_CompilerHints const&) (xqueryimpl.cpp:540)
==6659== by 0x415341: compileAndExecute(zorba::Zorba*, ZorbaCMDProperties const&, zorba::SmartPtr<zorba::StaticContext>&, std::string const&, std::istream&, std::ostream&, TimingInfo&) (zorbacmd.cpp:770)
==6659== by 0x416CFD: main (zorbacmd.cpp:1201)
==6659== Address 0x10 is not stack'd, malloc'd or (recently) free'd
==6659==